Conservation Laws

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If the speed of a moving object doubles, the amount of mechanical kinetic energy that it possesses ____.
1. decreases by two times
2. increases by two times
3. increases by four times
4. decreases by four times
When the brakes are fully applied, compared to the energy required to stop a car going 30 miles per hour, the energy needed to stop a car going 90 miles per hour is ____.
1. the same
2. 9 times as great
3. 6 times as great
4. 3 times as great
What is g?
1. about 10 m/s^2 down
2. all of these
3. the acceleration due to gravity
4. about -10 m/s^2
An object falls without friction near Earth’s surface. The loss of its potential energy is equal to its ____.
1. loss of mass
2. loss of height
3. gain in kinetic energy
4. gain in velocity
If the speed of a moving object triples, the amount of mechanical kinetic energy that it possesses ____.
1. increases by three times
2. increases by nine times
3. decreases by three times
4. decreases by nine times
A 20-kilogram object falls 2.0 meters to the floor. At what point in its fall does the kinetic energy of a body equal its potential energy?
1. Just the instant before it hits the floor
2. At all points of the fall
3. Very nearly at the top of the fall
4. Halfway to the floor
An object that has kinetic energy must be ____.
1. at rest
2. falling
3. moving
4. at an elevated position
What does the value “2.0 meters” represent?
1. change in height
2. mass
3. change in speed
4. force
Which equation would allow you to calculate the potential energy of the barbell?
1. red
2. green
3. purple
4. blue
Energy that is stored due to the position of an object may be called ____ energy.
1. radiant
2. potential
3. nuclear
4. kinetic
The ability to cause change is defined as ____.
1. force; measured in newtons
2. impulse; measured in newton-seconds
3. power; measured in watts
4. energy; measured in joules
Potential energy increases as a marble ____.
1. rolls at uniform speed on a level table
2. slows rolling up an incline
3. sits motionless on the floor
4. increases speed down an incline
Which equation would allow you to calculate the mechanical kinetic energy of the rolling ball?
1. green
2. red
3. violet
4. blue
The increase in the barbell’s potential energy is about ____.
1. 140 joules
2. 35 joules
3. 350 joules
4. 1,400 joules
What does the value “70-kilogram” represent?
1. change in speed
2. force
3. change in height
4. mass
The amount of mechanical kinetic energy possessed by the rolling ball is ____ joules.
1. 0.63
2. 1.6
3. 0.78
4. 0.31
What does the value “2.5 meters per second” represent?
1. force
2. distance
3. mass
4. speed
Two objects, A and B, have the same size and shape, but A is twice as heavy as B. When they are dropped simultaneously from a tower, they reach the ground at the same time, but A has greater ____.
1. acceleration
2. all of these
3. kinetic energy
4. speed
What does the value “0.25-kilogram” represent?
1. distance
2. mass
3. speed
4. force

Conservation Laws - Energy

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