6th Grade TEST - Chapter20 ONLINE REVIEW
True/False
Indicate whether the statement is true or false.
____ 1. Water waves can move a piece of cork floating on top of the water only in an up and down motion.
____ 2. Mechanical waves can travel in any type of medium.
____ 3. Radio waves are the only type of electromagnetic wave that is a transverse wave.
____ 4. Sound waves are compressional waves.
____ 5. The amplitude of a wave is the distance between a point on one wave and the identical point on the next wave.
____ 6. In general, the more energy a wave has the greater its amplitude.
____ 7. The speed of light depends on the medium it travels through.
____ 8. You can see yourself in a mirror because of the wave property called interference.
____ 9. Refraction occurs when the amplitude of a wave changes as it goes from one medium to another.
____ 10. You can hear sounds around the corner of a door due to the wave property called diffraction.
____ 11. High-pitched sounds have high frequencies, and low-pitched sounds wave low frequencies.
____ 12. Amplitude and frequency may vary in waves, but all waves travel at the same speed.
____ 13. Waves travel in straight lines and therefore cannot bend as they pass through a narrow opening.
____ 14. Mechanical waves transmit matter, while electromagnetic waves transmit energy.
____ 15. When you watch lightning, the light reaches you before the sound of the accompanying thunder because light travels faster than sound.
____ 16. Diffraction causes diamonds and other gems to sparkle.
____ 17. In a mechanical compressional wave, the wave energy causes the matter in the medium to move up and down or back and forth at right angles to the direction the wave travels.
____ 18. A group of molecules that are squeezed together is called a compression.
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 19. What is the best description of a wave?
a.
A wave transfers matter from one place to another.
b.
A wave transfers energy from one place to another.
c.
A wave transfers both energy and matter.
d.
A wave moves matter from one place to another.
____ 20. What kind of wave is created when an up and down motion of a rope produces right angles?
a.
compressional wave
b.
sound wave
c.
tranverse wave
d.
electromagnetic wave
____ 21. What kinds of waves do satellites use to transmit their locations to global positioning systems?
a.
electromagnetic radio waves
b.
infrared waves
c.
ultraviolet waves
d.
visible light waves
____ 22. What is the scientific term used to describe the amount of energy transferred by a wave?
a.
amplitude
b.
compression
c.
frequency
d.
vibration
____ 23. The school band is practicing their scales. As the pitch and frequency of the notes increases, what happens to the wavelength of the notes?
a.
The wavelength increases.
b.
The wavelength decreases then increases.
c.
The wavelength stays the same.
d.
The wavelength decreases.
____ 24. From the information on the chart, what can you conclude about the way sound travels?
a.
Sound waves travel faster as the temperature decreases.
b.
Sound waves travel more slowly through air.
c.
Sound waves travel faster as the temperature increases.
d.
Sound waves travel at a constant speed in all temperatures.
____ 25.
What kind of sound is an echo?
a.
diffraction
b.
reflection
c.
refraction
d.
vibration
____ 26. When the band is practicing in the music room, you can hear the music as it passes through the hallway. What property of sound does this example describe?
a.
amplification
b.
diffraction
c.
refraction
d.
vibration
____ 27. What happens when two waves meet?
a.
They collide and change direction.
b.
They collide and continue moving.
c.
They pass through each other and continue moving.
d.
They crash together and form a tsunami.
____ 28. When two waves overlap, they combine to form a new wave. What is this characteristic called?
a.
crest
b.
diffraction
c.
interference
d.
trough
____ 29. You are giving a presentation in science class about sound. You describe how the noise produced by the motor of a lawn mower hurts your ears.What term would you use to explain the way that you would reduce the noise of the mower?
a.
constructive interference
b.
destructive interference
c.
reflected sound
d.
refracted sound
____ 30. What kind of a wave travels along the coils of a spring?
a.
amplitude
b.
compressional
c.
frequency
d.
transverse
____ 31. The electromagnetic spectrum shows the range of electromagnetic waves. The wavelengths decrease at the bottom of the spectrum and increase at the top. What is the explanation for the range of wavelengths?
a.
Each wavelength is a different distance from the sun.
b.
Each wavelength has a different amplitude of vibration.
c.
Each wavelength has a different level of refraction.
d.
Each wavelength has a different frequency.
____ 32. Which one of the following is NOT an example of a mechanical wave?
a.
sound wave
c.
earthquake wave
b.
water wave
d.
radio wave
____ 33. Which one of the following is NOT an example of an electromagnetic wave?
a.
sound wave
c.
red light
b.
x-rays
d.
gamma rays
____ 34. Which one of the following is NOT an example of a compressional wave?
a.
wave moving through a coiled spring
b.
sound traveling through the air
c.
sound traveling through water
d.
green light traveling through the air
____ 35. Tsunamis have a large amount of energy because of their large ____.
a.
wavelength
c.
frequency
b.
amplitude
d.
diffraction
____ 36. Which one of the following determines the color of a light wave?
a.
amplitude only
c.
wavelength and frequency
b.
wavelength and amplitude
d.
interference patterns
____ 37. A place where molecules are far apart is a ____.
a.
refraction
c.
rarefaction
b.
reflection
d.
compression
____ 38. The speed of sound through air is about ____.
a.
340 m/s
c.
3,000,000 m/s
b.
2,000,000 m/s
d.
3,000,000 m/hour
____ 39. When light bounces off a surface it is called ____.
a.
reflection
c.
diffraction
b.
refraction
d.
interference
____ 40. In which one of the following cases will refraction occur?
a.
light traveling from air to glass
b.
light reflecting off of a mirror
c.
light bending around the corner of a door
d.
green light interfering with blue light
____ 41. Constructive interference occurs when waves meet ____.
a.
crest-to-crest and trough-to-trough
b.
crest-to-trough and crest-to-trough
c.
trough-to-crest and trough-to-crest
d.
crest-to-crest
____ 42. Waves can ____ when they move from one medium to another.
a.
disappear
c.
bend
b.
interfere
d.
split
____ 43. A(n) ____ wave DOES NOT need matter for energy transfer.
a.
electromagnetic
c.
compressional
b.
mechanical
d.
sound
____ 44. In a mechanical ____ wave, matter moves at a right angle to the wave direction.
a.
compressional
c.
light
b.
transverse
d.
electromagnetic
____ 45. The speed of sound in water is ____ the speed of sound in air.
a.
greater than
c.
equal to
b.
less than
d.
not greater than
____ 46. A region of spread-out particles in a compressional wave is called a(n) ____.
a.
compression
c.
interference
b.
rarefaction
d.
medium
____ 47. Waves can combine with each other; this is called ____.
a.
interference
c.
compression
b.
wave addition
d.
rarefaction
____ 48. Wave frequency is the ____ of waves passing a given point per second.
a.
amplitude
c.
speed
b.
wavelength
d.
number
____ 49. In a(n) ____ wave, matter moves back and forth in the same direction as the wave.
a.
compressional
c.
light
b.
transverse
d.
electromagnetic
____ 50. The action of a wave bouncing off a surface is called ____.
a.
rarefaction
c.
reflection
b.
refraction
d.
diffraction
____ 51. Amplitude reflects the amount of ____ in a wave.
a.
energy
c.
rarefaction
b.
compression
d.
speed
____ 52. A(n) ____ is the distance between a point on one wave and the identical point on the next wave.
a.
amplitude
c.
frequency
b.
wavelength
d.
compression
____ 53. The ____ of waves can change when the waves move from one medium to another.
a.
altitude
c.
speed
b.
amplitude
d.
compression
____ 54. A mechanical wave can travel only through ____.
a.
air
c.
matter
b.
water
d.
a vacuum
____ 55. The action of a wave bending around a barrier is called ____.
a.
reflection
c.
refraction
b.
diffraction
d.
rarefaction
____ 56. For significant ____ to occur, the wavelengths should match the size of the opening they are passing through.
a.
reflection
c.
refraction
b.
diffraction
d.
rarefaction
Completion
Complete each statement.
57. Waves are rhythmic disturbances that carry energy through matter or space without transferring ____________________.
58. Since sound is a mechanical wave it needs a ____________________ to travel through.
59. Waves that do not require matter to transfer energy are ____________________ waves.
60. ____________________ waves can be either transverse or compressional.
61. The less dense area of a compressional wave is called a(n) ____________________.
62. In a compressional wave, the amount of compression is like the ____________________ of a transverse wave.
63. The ____________________ is the unit of measure for the frequency of wavelengths per second.
64. Sound travels faster in ____________________ than in liquids.
65. An electromagnetic wave is slowed down if many ____________________ are in the medium.
66. Hertz can be described as ____________________.
67. The echo of a sound wave is due to ____________________ of the sound wave.
68. When light slows down as it passes from air to water it bends toward the ____________________.
69. The change in direction of waves when the wave travels from air to glass is ____________________.
70. Diffraction occurs when waves ____________________ around the edge of a barrier.
71. When two waves interact and their amplitudes cancel out, ____________________ interference has occurred.
72. Waves are ____________________ if they bounce off a surface.
73. Mechanical waves can be transverse or ____________________ waves.
74. The property of waves that allows them to bend around a barrier is ____________________.
75. Waves may bend if they move from one ____________________ to another.
76. Waves do not carry matter, but they do carry ____________________.
77. Wavelength, frequency, amplitude, and ____________________ are four characteristics of waves that can change.
78. In visible light, color is an indication of ____________________.
79. The common name for the reflection of sound waves is an ____________________.
80. In a compressional wave, one wavelength is the distance between adjacent compressions or adjacent ____________________.
81. Light waves travel more ____________________ as they enter water.
82. When light is reflected from a rough surface, the reflected light ____________________, producing no image.
83. Waves ____________________ best when their wavelength is similar in size to the opening they are moving through.
Matching
Match each item with the correct statement below.
a.
compressional wave
d.
mechanical wave
b.
electromagnetic wave
e.
transverse wave
c.
interference
____ 84. does not require a medium to travel through
____ 85. light waves and water waves are examples of this
____ 86. interaction of various different waves
____ 87. can be either transverse or compressional
____ 88. sound waves are an example of this
Match each item with the correct statement below.
a.
amplitude
d.
reflection
b.
diffraction
e.
refraction
c.
frequency
____ 89. the pitch of a sound wave
____ 90. why light shines off of a mirror
____ 91. related to the energy of a wave
____ 92. the changing of the speed of a wave
____ 93. the spreading out of waves around a barrier
Match each term with the correct description below.
a.
amplitude
j.
medium
b.
compression
k.
wave speed
c.
compressional wave
l.
rarefaction
d.
diffraction
m.
reflection
e.
electromagnetic wave
n.
refraction
f.
frequency
o.
transverse wave
g.
constructive interference
p.
wave
h.
destructive interference
q.
wavelength
i.
mechanical wave
____ 94. Squeezing a group of particles in a wave
____ 95. A transverse or compressional wave that can travel only through matter
____ 96. The matter through which a wave transfers energy
____ 97. A wave bends around a barrier
____ 98. A mechanical wave in which matter moves at right angles to the wave direction
____ 99. A wave in which matter moves back and forth in the direction the wave is moving
____ 100. A wave that doesn’t require matter to transfer energy
____ 101. A region of spread-out particles in a wave
____ 102. The distance from the crest or trough of a wave to the rest position
____ 103. The action of a wave bouncing off an object
____ 104. The number of waves passing a given point per second
____ 105. The product of wavelength and frequency
____ 106. A combination of waves form a smaller wave
____ 107. A combination of waves form a larger wave
____ 108. A rhythmic disturbance that carries energy
____ 109. A wave bends as it moves from one medium to another
____ 110. The distance between a point on a wave and the identical point on the next wave
Short Answer
111.
Explain how electromagnetic waves emitted by the sun affect you everyday.
112.
A boat in a lake is subjected to passing water waves. Describe the motion of the boat.
113.
Describe why you could not hear someone talk if you were both on the surface of the Moon.
114.
How can light travel from the Sun to Earth through the vacuum of space?
115.
How do your vocal cords produce sounds?
116.
Explain why a bright light differs from a dim light in terms of the amplitudes of each light wave.
117.
An instrument plays a pitch of 266 Hz. Another identical instrument plays a pitch of 400 Hz. How do the wavelength of each of these sound waves compare?
118.
Light that reflects off some surfaces can cause glare. Why don't all surfaces cause glare?
119.
A pencil is placed in a bucket of water. In some views, the pencil in the water will look bent when compared to the pencil above the water. Why is this so?
120.
Why is diffraction of light hard to detect?
121.
Describe how ear protectors help protect against hearing damage.
122. Study the following diagram. Then label the wave using the terms from the list.
amplitude
crest
trough
wavelength
123. Explain how the destructive interference of sound waves can help preserve hearing.
124. If the statement or term identifies a mechanical wave, list its letter under Mechanical Wave. If it identifies an electromagnetic wave, list its letter under Electromagnetic Wave. One or more terms might belong in both categories.
a. radio wave
d. visible light
g. transverse wave
b. sound wave
e. ocean wave
h. tidal wave
c. x rays
f. compressional wave
i. microwave
Mechanical Wave
Electromagnetic Wave
_____
_____
_____
_____
_____
_____
_____
_____
_____
_____
_____
_____
125. Compare and contrast transverse waves and compressional waves, and give an example of each type.
126. Calculate the wave speed of a 500-Hz wave with a wavelength of 0.5 m. First write the equation, then solve the problem, showing your work.
127. Assume that you hear a very low but very loud sound. What can you infer about the frequency and the amplitude of the sound waves you hear?
Problem
Figure 16-1
128. In Figure 16-1, what is the wavelength of Wave A?
129. In Figure 16-1, what is the wavelength of Wave B?
130. In Figure 16-1, what is the amplitude of Wave A.
131. In Figure 16-1, what is the amplitude of Wave B?
132. In Figure 16-1, which wave has the greater frequency?
133. In Figure 16-1, which wave has the least amount of energy?
134. When sunlight passes through a piece of glass known as a prism, the sunlight gets separated into the colors of the rainbow. Use the concept of refraction to explain how this occurs.
Essay
135.
Explain the differences and similarities between waves and particles.
Identify and explain what is responsible for each of the following effects.
136. You see a car behind you in the rearview mirror of your car.
137. You see a coin at the bottom of a fountain of water, but when you reach for it, it is in a different place than it appears to be.
138. You are in a cave with light coming in through a narrow crack in the ceiling. You can see a distinct beam of light on the floor, and you can see features of the cave illuminated by dim light.
139. Members of an orchestra tune their instruments before they begin to play. This produces a blast of confusing, disharmonious noise. When they begin to play in unison, the music from each instrument group is clear and loud. Explain these effects in terms of two types of interference.
Monday, December 17, 2007
7th Grade - Chapter 5 Test Review
7th Grade REVIEW TEST - Chpater 5
True/False
Indicate whether the statement is true or false.
____ 1. When you perform work on an object you increase the energy of the object.
____ 2. A force at any angle to the direction of motion can perform work.
____ 3. Work is measured in joules.
____ 4. All forms of energy can do work.
____ 5. Under certain conditions, it is possible to get more work out of a machine than you put into it.
____ 6. Power is the rate at which a force is applied.
____ 7. The unit of power is the watt.
____ 8. Machines may allow you to do less work over a longer distance.
____ 9. The thread around a screw is a lever.
____ 10. The mechanical advantage of a wheel and axle is the radius of the wheel divided by the radius of the axle.
____ 11. A broom is an example of a wedge.
____ 12. Power and work are interchangeable terms.
____ 13. If you use a ramp that is 6 m long to move an object upward 1 m, then the mechanical advantage of the ramp is 6.
____ 14. You are doing NO work when you hold your 23-kg dog in your arms.
____ 15. You do 1 J of work if you use a force of 1 N for a distance of 1 m.
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 16. Which is NOT an example of a compound machine?
a.
bicycle
b.
can opener
c.
pulley
d.
scissor
____ 17. Jacob is pushing a shopping cart down a supermarket aisle. He is exerting forces in different directions on the shopping cart handle. Which force is doing the work?
a.
downward force
b.
forward force
c.
right angle force
d.
upward force
____ 18. Which response best describes power?
a.
The distance an object is moved.
b.
The force exerted on an object.
c.
The motion of an object.
d.
The rate at which work is done.
____ 19. In which way can a machine NOT make work easier?
a.
changing the amount of force needed
b.
changing the distance over which force is exerted
c.
changing the direction in which force is exerted
d.
changing the work by creating a new force
____ 20. Joey used a knife to cut a piece of bread. What is the work he applied to the knife called?
a.
friction
b.
input force
c.
mechanical advantage
d.
output force
____ 21. Hu made a chart to show the efficiency of three different machines.
Which machine has the highest ratio of output work to input work?
a.
Machine 1
b.
Machine 2
c.
Machine 3
d.
cannot tell
____ 22. Which is an example of a wheel and axle?
a.
baseball bat
b.
doorknob
c.
pulley
d.
screw
____ 23. How are an inclined plane and a wedge alike?
a.
Both have a flat, sloped surface.
b.
Both are compound machines.
c.
Both have the same mechanical advantage.
d.
Both have the same output force.
____ 24. Darren draws a diagram to show the forces exerted on an object. The arrows represent equal forces on the object.
How will the object be affected by the two equal forces?
a.
It will break.
b.
It will change direction.
c.
It will not be affected.
d.
It will not move.
____ 25. Which word best describes the ratio of an output force to an input force?
a.
distance
b.
efficiency
c.
friction
d.
mechanical advantage
____ 26. How does friction affect a machine’s efficiency?
a.
It increases it.
b.
It decreases it.
c.
It keeps it consistent.
d.
It does not affect it.
____ 27. The work equation states that work in joules equals force in newtons times distance in meters. If Sarah carries a box that weighs 35 N a distance of 3 m, how much work did she do?
a.
38 J
b.
70 J
c.
105 J
d.
175 J
____ 28. Tammy is standing still while holding a ten-pound bowling ball. Is she doing work?
a.
Yes, the ball is heavy.
b.
Yes, she is exerting a force on the object.
c.
No, she is not making the object move.
d.
No, she is exerting a force on the ground.
____ 29. Which one of the following is NOT an example of work being done?
a.
the Moon orbiting Earth
b.
pushing a box from the bottom of a hill to the top of the hill
c.
pulling a sled across a field covered with snow
d.
lifting a bookbag off the floor
____ 30. A fixed, single pulley that is used to lift a block does which one of the following?
a.
doubles the force required to lift the block
b.
decreases the force required to lift the block
c.
makes the block easier to lift by changing the direction of the force needed to lift it
d.
decreases the force required and changes the direction of the force required
____ 31. A slanted surface used to raise an object is a(n)____.
a.
efficiency board
c.
inclined plane
b.
effort ramp
d.
wedge
____ 32. A device that does work with only one movement and changes the size or direction of a force is a(n) ____.
a.
compound machine
c.
screw
b.
effort machine
d.
simple machine
____ 33. A bar that is free to pivot about a fixed point is a ____.
a.
fulcrum
c.
ramp
b.
lever
d.
wedge
____ 34. The rate at which work is done is called ____.
a.
efficiency
c.
force
b.
effort time
d.
power
____ 35. The work output of a machine divided by the work input is the ____ of the machine.
a.
efficiency
c.
power
b.
effort
d.
resistance
____ 36. The amount by which a machine multiplies an input force is called the ____.
a.
efficiency factor
c.
mechanical advantage
b.
fulcrum
d.
resistance force
____ 37. An inclined plane with one or two sloping sides forms a machine called a ____.
a.
pulley
c.
ramp
b.
lever
d.
wedge
____ 38. An inclined plane wrapped around a cylinder post is a ____.
a.
lever
c.
screw
b.
ramp
d.
wedge
____ 39. A machine that changes only the direction of a force has a mechanical advantage of ____.
a.
1
c.
10
b.
2
d.
100
____ 40. A winding mountain road is an example of a(n) ____.
a.
lever
c.
wedge
b.
inclined plane
d.
wheel and axle
____ 41. When two or more simple machines work together, they are called a(n) ____.
a.
compound machine
c.
screw
b.
effort machine
d.
simple machine
____ 42. A lever with a mechanical advantage greater than 1 is used to ____.
a.
change direction
c.
increase force
b.
increase distance
d.
decrease force
____ 43. Three of the following simple machines are basically the same. The one that does NOT belong with the group is the ____.
a.
lever
c.
wedge
b.
pulley
d.
wheel and axle
____ 44. An object is moving due east. You push the object. Work is being done at all times when you push ____.
a.
due west
c.
straight down
b.
due east
d.
at a 45° angle
____ 45. A ____ is an example of a compound machine.
a.
lawnmower
c.
baseball bat
b.
shovel
d.
wheel and axle
____ 46. The mechanical advantage tells you the number of times a machine increases the ____.
a.
net force
c.
output force
b.
stable force
d.
input force
____ 47. Work is equal to force times ____.
a.
power
c.
joules
b.
distance
d.
energy
____ 48. Power is measured in J per ____.
a.
watt
c.
minute
b.
hour
d.
second
____ 49. In order for work to be done, an object must ____.
a.
have mass
c.
have muscles
b.
move in the direction of the force
d.
move at a right angle to the force
____ 50. Machines let you use less force over a greater ____.
a.
distance
c.
weight
b.
mass
d.
exertion
____ 51. NO work is being done when you ____ a ball.
a.
hit
c.
carry
b.
catch
d.
drop
____ 52. When the Egyptians built the pyramids, they used the idea that a large force over a short distance can be accomplished by the same work as a small force over a ____ distance.
a.
changing
c.
shorter
b.
minimum
d.
long
____ 53. ____ describes the rate at which work is being done.
a.
Joules
c.
Effort force
b.
Power
d.
Efficiency
____ 54. A ____ is NOT a simple machine.
a.
wrench
c.
tooth
b.
shovel
d.
teeter-totter
____ 55. The pivot point of a lever is called a ____.
a.
wedge
c.
fulcrum
b.
screw
d.
wheel and axle
____ 56. Power is expressed in units of ____.
a.
light
c.
joules
b.
watts
d.
surges
____ 57. A(n) ____ is a moving inclined plane.
a.
teeter-totter
c.
elevator
b.
staircase
d.
wedge
Completion
Complete each statement.
58. When force is _________________________ to the direction of motion, no work is done.
59. A joule is equal to one ____________________ times one meter.
60. When you use a crowbar to lift a large rock, you are working against the force called ____________________.
61. Power describes the ____________________ at which work is being done.
62. Unlike a fixed pulley, a movable pulley ____________________ the input force.
63. Doorknobs and faucet handles are examples of a simple machine called a(n) ______________________________.
64. An ideal machine has an efficiency of ____________________.
65. The pivot point of a lever is called the ____________________.
66. A machine made of several simple machines is called a(n) ______________________________.
67. When a machine is used to perform a task, work output is always ____________________ than work input.
Choose the term in parentheses that correctly completes the sentence.
68. A blender is a ____________________ (simple, compound, pulley) machine.
69. The mechanical advantage that makes work easiest is one that is ____________________ (large, small, zero).
70. Holding a watermelon in your hands is an example of ____________________ (work, no work) being done.
71. A goalie stopping a hockey puck is an example of ____________________ (work, no work) being done.
72. Power does NOT depend on ____________________ (work done, muscles, time).
73. As you increase the effort distance, you ____________________ (decrease, increase, stabilize) the effort force needed.
74. The mechanical advantage tells you the number of times a machine ____________________ (increases, decreases, eliminates) the effort force.
75. A ____________________ (shovel, crowbar, potter’s wheel) is NOT an example of a lever.
76. An ideal machine has an efficiency ____________________ (less than one, equal to one, greater than one).
77. ____________________ (Heat, Friction, Work) is NOT a source of energy loss in a machine.
Matching
Match each term with the following questions.
a.
input force
d.
output force
b.
efficiency
e.
compound machine
c.
mechanical advantage
____ 78. ratio of output force to input force
____ 79. force you apply to a simple machine
____ 80. force you overcome when using a simple machine
____ 81. device made of more than one simple machine
____ 82. ability of a machine to convert work input into work output
Match each simple machine with the machines below.
a.
inclined plane
d.
lever
b.
wedge
e.
wheel and axle
c.
screw
____ 83. knife
____ 84. leaf rake
____ 85. wheelchair ramp
____ 86. potter's wheel
____ 87. threaded bolt
Match each item with the correct description below.
a.
simple machine
j.
watt
b.
work
k.
ideal machine
c.
input force
l.
screw
d.
inclined plane
m.
pulley
e.
joule
n.
mechanical advantage
f.
output force
o.
efficiency
g.
power
p.
fulcrum
h.
machine
q.
wheel and axle
i.
friction
r.
wedge
____ 88. a device that makes work easier by changing the size or direction of the applied force
____ 89. SI unit for work
____ 90. causes the output work of a machine to be less than the input work
____ 91. the rate at which work is being done
____ 92. the ratio of the output force to the input force
____ 93. a moving inclined plane
____ 94. has only one movement
____ 95. the unit of measurement of power
____ 96. two rigidly attached wheels that rotate together
____ 97. a sloped surface
____ 98. exertion of a force on an object that produces motion in the direction of the force
____ 99. the force a machine exerts
____ 100. a machine’s ability to convert work input into work output
____ 101. machine with 100% efficiency
____ 102. the pivot point of a lever
____ 103. an inclined plane wrapped around a shaft
____ 104. a grooved wheel that redirects force using a rope
____ 105. the effort force you exert
Short Answer
106.
Explain how a wheel and axle works and give examples of objects that use a wheel and axle.
107.
Sharon wants to know if friction will affect the efficiency of a ramp that she built. She will form a hypothesis and then test it.
Part A Write a hypothesis that Sharon can test.
Part B Write a plan that shows how Sharon can test her hypothesis.
108.
What does work depend on in scientific terms?
109.
You swing a rope in a circle. Are you doing work on the rope? Why or why not?
110.
Which one of the following could be the mechanical advantage of a third-class lever: 0.7, 1.5, 10.5, or 3.0? Explain your answer.
111.
An inventor claims to have built a machine that can produce 120 J of work with an input of 110 J. Would you believe the inventor's claim? Why or why not?
112.
Explain why tin snips, designed for cutting metal, have long handles and short blades.
113.
How are work, time, and power related?
114.
Gears are modified wheel-and-axle machines. Explain how to calculate the mechanical advantage of a pair of gears.
115.
A 700-watt gasoline engine and a 300-watt electric motor both do 3 J of work. Which machine can do the work faster? Explain your answer.
116.
How does low air pressure in bicycle tires reduce the efficiency of a bicycle?
117.
Give one example of a compound machine and list the simple machines that make it up.
118.
Do machines make work easier? Explain your answer.
119.
How does oil reduce friction between two surfaces?
120.
Explain how your teeth work as a wedge.
121.
Explain the transfer of energy during work.
Complete the table below by calculating the missing values. Then answer the following questions.
Situation
Force
Distance
Time
Work
Power
1. A
200 N
50 m
10 s
2. B
100 N
6 m
200 W
3. C
200 N
100 m
10 s
4. D
200 N
10 s
5000 J
122. What are the missing values in line 1?
123. What are the missing values in line 2?
124. What are the missing values in line 3?
125. What are the missing values in line 4?
126. In which situation was the most work done?
127. In which situation was the most power used?
128. How does the work done in situation D compare to that done in situation A?
129. How does the distance in situation D compare to the distance in situation A?
130. What would happen to the power in situation C if the time doubled?
131. Compare and contrast simple and compound machines.
132. Compare and contrast a screw and a wedge.
133. What is the work done in using a force of 200 N to push a box 15 m?
134. What is the power used if it took 2,000 J to move a box in 8 s?
135. What is the mechanical advantage of using a machine if you use an input force of 25 N to overcome an output force of 125 N?
136. If an output force of 50 N is used to move an object a distance of 20 m, what distance must the object be moved if the input force is 10 N, so that work in = work out?
137. What is the efficiency of a machine if the work input is 75 N and the work output is 25 N?
Problem
138.
You use 200 N of force to push a snow shovel 10 m along the ground. How much work was done?
139.
A painter lifts a 3 kg can of paint 3 m above the floor. How much work was done?
140.
How much power is needed to do 1,000 J of work on a box if it takes 50 s to lift it?
141.
How much work is done if 500 W of power is used over 2 min?
142.
Calculate the mechanical advantage of a lever where 5 N of input force is needed to move a 10 N box using that lever.
143.
A carpenter uses a claw hammer to pull a nail from a board. The nail has a resistance of 1,500 N. The carpenter applies a force of 150 N. What is the mechanical advantage of the hammer?
Essay
144. Name the six types of simple machines and give an example of each, or what each might be used to do.
145. Explain why applying force to an object does not always result in work being done.
146. Even though work input should equal work output, explain why, other than on ideal machines, machines have an efficiency less than one.
147. If a machine cannot have more work output than work input, what advantage is there to using one?
148. Compare and contrast fixed pulleys with movable pulleys and pulley systems and discuss their respective mechanical advantages.
True/False
Indicate whether the statement is true or false.
____ 1. When you perform work on an object you increase the energy of the object.
____ 2. A force at any angle to the direction of motion can perform work.
____ 3. Work is measured in joules.
____ 4. All forms of energy can do work.
____ 5. Under certain conditions, it is possible to get more work out of a machine than you put into it.
____ 6. Power is the rate at which a force is applied.
____ 7. The unit of power is the watt.
____ 8. Machines may allow you to do less work over a longer distance.
____ 9. The thread around a screw is a lever.
____ 10. The mechanical advantage of a wheel and axle is the radius of the wheel divided by the radius of the axle.
____ 11. A broom is an example of a wedge.
____ 12. Power and work are interchangeable terms.
____ 13. If you use a ramp that is 6 m long to move an object upward 1 m, then the mechanical advantage of the ramp is 6.
____ 14. You are doing NO work when you hold your 23-kg dog in your arms.
____ 15. You do 1 J of work if you use a force of 1 N for a distance of 1 m.
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 16. Which is NOT an example of a compound machine?
a.
bicycle
b.
can opener
c.
pulley
d.
scissor
____ 17. Jacob is pushing a shopping cart down a supermarket aisle. He is exerting forces in different directions on the shopping cart handle. Which force is doing the work?
a.
downward force
b.
forward force
c.
right angle force
d.
upward force
____ 18. Which response best describes power?
a.
The distance an object is moved.
b.
The force exerted on an object.
c.
The motion of an object.
d.
The rate at which work is done.
____ 19. In which way can a machine NOT make work easier?
a.
changing the amount of force needed
b.
changing the distance over which force is exerted
c.
changing the direction in which force is exerted
d.
changing the work by creating a new force
____ 20. Joey used a knife to cut a piece of bread. What is the work he applied to the knife called?
a.
friction
b.
input force
c.
mechanical advantage
d.
output force
____ 21. Hu made a chart to show the efficiency of three different machines.
Which machine has the highest ratio of output work to input work?
a.
Machine 1
b.
Machine 2
c.
Machine 3
d.
cannot tell
____ 22. Which is an example of a wheel and axle?
a.
baseball bat
b.
doorknob
c.
pulley
d.
screw
____ 23. How are an inclined plane and a wedge alike?
a.
Both have a flat, sloped surface.
b.
Both are compound machines.
c.
Both have the same mechanical advantage.
d.
Both have the same output force.
____ 24. Darren draws a diagram to show the forces exerted on an object. The arrows represent equal forces on the object.
How will the object be affected by the two equal forces?
a.
It will break.
b.
It will change direction.
c.
It will not be affected.
d.
It will not move.
____ 25. Which word best describes the ratio of an output force to an input force?
a.
distance
b.
efficiency
c.
friction
d.
mechanical advantage
____ 26. How does friction affect a machine’s efficiency?
a.
It increases it.
b.
It decreases it.
c.
It keeps it consistent.
d.
It does not affect it.
____ 27. The work equation states that work in joules equals force in newtons times distance in meters. If Sarah carries a box that weighs 35 N a distance of 3 m, how much work did she do?
a.
38 J
b.
70 J
c.
105 J
d.
175 J
____ 28. Tammy is standing still while holding a ten-pound bowling ball. Is she doing work?
a.
Yes, the ball is heavy.
b.
Yes, she is exerting a force on the object.
c.
No, she is not making the object move.
d.
No, she is exerting a force on the ground.
____ 29. Which one of the following is NOT an example of work being done?
a.
the Moon orbiting Earth
b.
pushing a box from the bottom of a hill to the top of the hill
c.
pulling a sled across a field covered with snow
d.
lifting a bookbag off the floor
____ 30. A fixed, single pulley that is used to lift a block does which one of the following?
a.
doubles the force required to lift the block
b.
decreases the force required to lift the block
c.
makes the block easier to lift by changing the direction of the force needed to lift it
d.
decreases the force required and changes the direction of the force required
____ 31. A slanted surface used to raise an object is a(n)____.
a.
efficiency board
c.
inclined plane
b.
effort ramp
d.
wedge
____ 32. A device that does work with only one movement and changes the size or direction of a force is a(n) ____.
a.
compound machine
c.
screw
b.
effort machine
d.
simple machine
____ 33. A bar that is free to pivot about a fixed point is a ____.
a.
fulcrum
c.
ramp
b.
lever
d.
wedge
____ 34. The rate at which work is done is called ____.
a.
efficiency
c.
force
b.
effort time
d.
power
____ 35. The work output of a machine divided by the work input is the ____ of the machine.
a.
efficiency
c.
power
b.
effort
d.
resistance
____ 36. The amount by which a machine multiplies an input force is called the ____.
a.
efficiency factor
c.
mechanical advantage
b.
fulcrum
d.
resistance force
____ 37. An inclined plane with one or two sloping sides forms a machine called a ____.
a.
pulley
c.
ramp
b.
lever
d.
wedge
____ 38. An inclined plane wrapped around a cylinder post is a ____.
a.
lever
c.
screw
b.
ramp
d.
wedge
____ 39. A machine that changes only the direction of a force has a mechanical advantage of ____.
a.
1
c.
10
b.
2
d.
100
____ 40. A winding mountain road is an example of a(n) ____.
a.
lever
c.
wedge
b.
inclined plane
d.
wheel and axle
____ 41. When two or more simple machines work together, they are called a(n) ____.
a.
compound machine
c.
screw
b.
effort machine
d.
simple machine
____ 42. A lever with a mechanical advantage greater than 1 is used to ____.
a.
change direction
c.
increase force
b.
increase distance
d.
decrease force
____ 43. Three of the following simple machines are basically the same. The one that does NOT belong with the group is the ____.
a.
lever
c.
wedge
b.
pulley
d.
wheel and axle
____ 44. An object is moving due east. You push the object. Work is being done at all times when you push ____.
a.
due west
c.
straight down
b.
due east
d.
at a 45° angle
____ 45. A ____ is an example of a compound machine.
a.
lawnmower
c.
baseball bat
b.
shovel
d.
wheel and axle
____ 46. The mechanical advantage tells you the number of times a machine increases the ____.
a.
net force
c.
output force
b.
stable force
d.
input force
____ 47. Work is equal to force times ____.
a.
power
c.
joules
b.
distance
d.
energy
____ 48. Power is measured in J per ____.
a.
watt
c.
minute
b.
hour
d.
second
____ 49. In order for work to be done, an object must ____.
a.
have mass
c.
have muscles
b.
move in the direction of the force
d.
move at a right angle to the force
____ 50. Machines let you use less force over a greater ____.
a.
distance
c.
weight
b.
mass
d.
exertion
____ 51. NO work is being done when you ____ a ball.
a.
hit
c.
carry
b.
catch
d.
drop
____ 52. When the Egyptians built the pyramids, they used the idea that a large force over a short distance can be accomplished by the same work as a small force over a ____ distance.
a.
changing
c.
shorter
b.
minimum
d.
long
____ 53. ____ describes the rate at which work is being done.
a.
Joules
c.
Effort force
b.
Power
d.
Efficiency
____ 54. A ____ is NOT a simple machine.
a.
wrench
c.
tooth
b.
shovel
d.
teeter-totter
____ 55. The pivot point of a lever is called a ____.
a.
wedge
c.
fulcrum
b.
screw
d.
wheel and axle
____ 56. Power is expressed in units of ____.
a.
light
c.
joules
b.
watts
d.
surges
____ 57. A(n) ____ is a moving inclined plane.
a.
teeter-totter
c.
elevator
b.
staircase
d.
wedge
Completion
Complete each statement.
58. When force is _________________________ to the direction of motion, no work is done.
59. A joule is equal to one ____________________ times one meter.
60. When you use a crowbar to lift a large rock, you are working against the force called ____________________.
61. Power describes the ____________________ at which work is being done.
62. Unlike a fixed pulley, a movable pulley ____________________ the input force.
63. Doorknobs and faucet handles are examples of a simple machine called a(n) ______________________________.
64. An ideal machine has an efficiency of ____________________.
65. The pivot point of a lever is called the ____________________.
66. A machine made of several simple machines is called a(n) ______________________________.
67. When a machine is used to perform a task, work output is always ____________________ than work input.
Choose the term in parentheses that correctly completes the sentence.
68. A blender is a ____________________ (simple, compound, pulley) machine.
69. The mechanical advantage that makes work easiest is one that is ____________________ (large, small, zero).
70. Holding a watermelon in your hands is an example of ____________________ (work, no work) being done.
71. A goalie stopping a hockey puck is an example of ____________________ (work, no work) being done.
72. Power does NOT depend on ____________________ (work done, muscles, time).
73. As you increase the effort distance, you ____________________ (decrease, increase, stabilize) the effort force needed.
74. The mechanical advantage tells you the number of times a machine ____________________ (increases, decreases, eliminates) the effort force.
75. A ____________________ (shovel, crowbar, potter’s wheel) is NOT an example of a lever.
76. An ideal machine has an efficiency ____________________ (less than one, equal to one, greater than one).
77. ____________________ (Heat, Friction, Work) is NOT a source of energy loss in a machine.
Matching
Match each term with the following questions.
a.
input force
d.
output force
b.
efficiency
e.
compound machine
c.
mechanical advantage
____ 78. ratio of output force to input force
____ 79. force you apply to a simple machine
____ 80. force you overcome when using a simple machine
____ 81. device made of more than one simple machine
____ 82. ability of a machine to convert work input into work output
Match each simple machine with the machines below.
a.
inclined plane
d.
lever
b.
wedge
e.
wheel and axle
c.
screw
____ 83. knife
____ 84. leaf rake
____ 85. wheelchair ramp
____ 86. potter's wheel
____ 87. threaded bolt
Match each item with the correct description below.
a.
simple machine
j.
watt
b.
work
k.
ideal machine
c.
input force
l.
screw
d.
inclined plane
m.
pulley
e.
joule
n.
mechanical advantage
f.
output force
o.
efficiency
g.
power
p.
fulcrum
h.
machine
q.
wheel and axle
i.
friction
r.
wedge
____ 88. a device that makes work easier by changing the size or direction of the applied force
____ 89. SI unit for work
____ 90. causes the output work of a machine to be less than the input work
____ 91. the rate at which work is being done
____ 92. the ratio of the output force to the input force
____ 93. a moving inclined plane
____ 94. has only one movement
____ 95. the unit of measurement of power
____ 96. two rigidly attached wheels that rotate together
____ 97. a sloped surface
____ 98. exertion of a force on an object that produces motion in the direction of the force
____ 99. the force a machine exerts
____ 100. a machine’s ability to convert work input into work output
____ 101. machine with 100% efficiency
____ 102. the pivot point of a lever
____ 103. an inclined plane wrapped around a shaft
____ 104. a grooved wheel that redirects force using a rope
____ 105. the effort force you exert
Short Answer
106.
Explain how a wheel and axle works and give examples of objects that use a wheel and axle.
107.
Sharon wants to know if friction will affect the efficiency of a ramp that she built. She will form a hypothesis and then test it.
Part A Write a hypothesis that Sharon can test.
Part B Write a plan that shows how Sharon can test her hypothesis.
108.
What does work depend on in scientific terms?
109.
You swing a rope in a circle. Are you doing work on the rope? Why or why not?
110.
Which one of the following could be the mechanical advantage of a third-class lever: 0.7, 1.5, 10.5, or 3.0? Explain your answer.
111.
An inventor claims to have built a machine that can produce 120 J of work with an input of 110 J. Would you believe the inventor's claim? Why or why not?
112.
Explain why tin snips, designed for cutting metal, have long handles and short blades.
113.
How are work, time, and power related?
114.
Gears are modified wheel-and-axle machines. Explain how to calculate the mechanical advantage of a pair of gears.
115.
A 700-watt gasoline engine and a 300-watt electric motor both do 3 J of work. Which machine can do the work faster? Explain your answer.
116.
How does low air pressure in bicycle tires reduce the efficiency of a bicycle?
117.
Give one example of a compound machine and list the simple machines that make it up.
118.
Do machines make work easier? Explain your answer.
119.
How does oil reduce friction between two surfaces?
120.
Explain how your teeth work as a wedge.
121.
Explain the transfer of energy during work.
Complete the table below by calculating the missing values. Then answer the following questions.
Situation
Force
Distance
Time
Work
Power
1. A
200 N
50 m
10 s
2. B
100 N
6 m
200 W
3. C
200 N
100 m
10 s
4. D
200 N
10 s
5000 J
122. What are the missing values in line 1?
123. What are the missing values in line 2?
124. What are the missing values in line 3?
125. What are the missing values in line 4?
126. In which situation was the most work done?
127. In which situation was the most power used?
128. How does the work done in situation D compare to that done in situation A?
129. How does the distance in situation D compare to the distance in situation A?
130. What would happen to the power in situation C if the time doubled?
131. Compare and contrast simple and compound machines.
132. Compare and contrast a screw and a wedge.
133. What is the work done in using a force of 200 N to push a box 15 m?
134. What is the power used if it took 2,000 J to move a box in 8 s?
135. What is the mechanical advantage of using a machine if you use an input force of 25 N to overcome an output force of 125 N?
136. If an output force of 50 N is used to move an object a distance of 20 m, what distance must the object be moved if the input force is 10 N, so that work in = work out?
137. What is the efficiency of a machine if the work input is 75 N and the work output is 25 N?
Problem
138.
You use 200 N of force to push a snow shovel 10 m along the ground. How much work was done?
139.
A painter lifts a 3 kg can of paint 3 m above the floor. How much work was done?
140.
How much power is needed to do 1,000 J of work on a box if it takes 50 s to lift it?
141.
How much work is done if 500 W of power is used over 2 min?
142.
Calculate the mechanical advantage of a lever where 5 N of input force is needed to move a 10 N box using that lever.
143.
A carpenter uses a claw hammer to pull a nail from a board. The nail has a resistance of 1,500 N. The carpenter applies a force of 150 N. What is the mechanical advantage of the hammer?
Essay
144. Name the six types of simple machines and give an example of each, or what each might be used to do.
145. Explain why applying force to an object does not always result in work being done.
146. Even though work input should equal work output, explain why, other than on ideal machines, machines have an efficiency less than one.
147. If a machine cannot have more work output than work input, what advantage is there to using one?
148. Compare and contrast fixed pulleys with movable pulleys and pulley systems and discuss their respective mechanical advantages.
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