Energy Transformations — Unit test Answers

A 440 kg roller coaster car is going 26 m/s when it reaches the lowest point on the track. If the car started from rest at the top of a hill, how much higher was that point on the track than the lowest point? (Use g = 9.80 m/s2, and ignore friction.)

A box is sliding along a frictionless surface and gets to a ramp. Disregarding friction, how fast should the box be going on the ground in order to slide up the ramp to a height of 2.5 meters, where it stops? (Use g = 9.8 m/s2.)

A 7.00 kg bowling ball is held 2.00 m above the ground. Using g = 9.80 m/s2, how much energy does the bowling ball have due to its position?

Brandi poses as Lady Justice for a skit in her government class. She holds a set of scales above her head with her right hand and a sword by her side in her left hand. She holds the pose for 10 minutes. At the end of the skit, she mentions to her friend that it was a lot of work to pose and that her arms were really tired.

Which change would cause the largest increase in a mountain climber’s gravitational potential energy?

When an object is not in motion, it can still have a form of energy. What form of energy does an object have due to its distance from Earth?

What is the unit for work?

A 60.0 kg runner is moving at 6.00 m/s and speeds up to 9.00 m/s. The runner’s change in kinetic energy is 1,350 J.How much work was done?

A load of bricks is lifted to the second floor of a building. How do work and power relate to this job?

Trevor is pulling his younger brother in a wagon. He pulls the wagon 50 m to the corner with a force that is parallel with the ground. He then turns the wagon around and pulls it 50 m back to the starting point with the same force at an angle of 30° with respect to the ground.

The image shows a pendulum that is released from rest at point A.

According to the work-energy theorem, the amount of work done can be determined using which formula?

A force of 75 N at an angle of 15° to the direction of motion moves a chair 3 m. Which change would result in more work being done on the chair?

Hiro walks up a flight of stairs in his apartment building. Later in the day, he runs up the same flight of stairs.

A blender takes in 180 J of electrical energy. Of the 180 J, 90 J are transformed into kinetic energy, 60 J are transformed into thermal energy, and the rest is transformed into sound.

In which scenario is elastic potential energy present?

The image shows a pendulum that is released from rest at point A. Shari tells her friend that no energy transformation occurs as the pendulum swings between point B and point D.

A compressed spring has 16.2 J of elastic potential energy when it is compressed 0.30 m. What is the spring constant of the spring?

In which scenario is an animal doing work? Check all that apply.

Irving, a cat, has a favorite toy that is made up of a squeaky ball at the end of a string. The toy makes up a closed system. Irving’s owner dangles the toy so that the ball swings down and then swings back up again.