Energy Review

Which of the following best describes the two variables that determine the kinetic energy of an object?

• mass and gravity

• mass and volume

• mass and velocity

• speed and velocity

Students record the mass, speed, and kinetic energy of objects moving along a track. The students create these data tables.

Which two statements correctly relate the mass and the speed of an object to its kinetic energy?

• When an object's speed doubles, its kinetic energy doubles.

• When an object's speed doubles, its kinetic energy more than doubles.

• When the mass of an object doubles, its kinetic energy doubles.

• When the mass of an object doubles, its kinetic energy more than doubles.

• When both the speed and the mass of an object double, its kinetic energy doubles.

The table shows four moving objects with different masses and speeds.

Which object has the most kinetic energy?

• Object 1

• Object 2

• Object 3

• Object 4

A bowling ball and baseball move at the same speed.

How does the kinetic energy of each ball compare, and why?

• The bowling ball has greater kinetic energy because it has more mass than the baseball.

• The baseball has greater kinetic energy because it has less mass than the bowling ball.

• The bowling ball has less kinetic energy because it has a larger volume than the baseball.

• The bowling ball and the baseball have the same kinetic energy because they have the same speed.

The image shows a roller coaster car at five positions along its track.

For which parts of the motion is some part of the kinetic energy of the car transformed into potential energy?

• when moving from 1 to 2 and 4 to 5

• when moving from 2 to 3 and 3 to 4

• when moving from 2 to 4 and 4 to 5

• when moving from 1 to 2 and 2 to 4

A pendulum is attached to a fixed point and then released with a swinging motion. Three positions (1, 2, and 3) are marked on the path of the pendulum as it swings, as shown in the image

If the energy of the pendulum follows the Law of Conservation of Energy, which table could represent the kinetic and potential energy values at the three positions?

• 
• 
• 
• 

The diagram shows the various energies possessed by a ball falling from a height of 20 m.

Which statement is an accurate conclusion made from the data?

• The total energy of the ball decreases during its fall.

• The total energy of the ball is equal to potential energy.

• The total energy of the ball remains constant during its fall.

• The total energy of the ball is converted into kinetic energy during its fall.

The diagram shows a child swinging on a swing set.

As the child moves from left to right, at which point will the maximum kinetic energy be reached?

• 1

• 2

• 3

• 4

A student pushed a toy car along a level track toward a spring. The car collided
with the spring, causing the spring to compress. After the spring decompressed,
the car traveled backward a short distance before stopping.

Which statement accurately explains the energy transformation that occurred during the collision with the spring?

• As the spring is releasing, kinetic energy in the spring is converted to kinetic energy in the car.

• As the spring is releasing, kinetic energy in the car is converted to elastic
  potential energy in the spring.

• As the car is compressing the spring, kinetic energy in the car is converted to elastic potential energy in the spring.

• As the car is compressing the spring, elastic potential energy in the spring is converted to kinetic energy in the car.

This is a diagram of a system that includes a girl and Earth. In the first picture, the girl sits on the motionless swing. Then she pushes herself backwards. In the second picture, the girl moves forward on the swing. The swing moves the girl back and forth.

Which of these best describes when the system has the greatest gravitational potential energy?

• when the girl is seated on the motionless swing

• 
  when the swing is at its highest point above the ground and begins moving down

• 
  when the swing is at its lowest point above the ground and begins moving up

• when the swing is moving at a constant speed