Kinetic and Potential Energy Problems

Name: ______Section: ______

Kinetic Energy

1.  You pedal your 20 kg bicycle at 3 m/s. What is the kinetic energy of your bicycle?

2.  While ice skating, a 50 kg student has a kinetic energy of 2025J. What is the student’s velocity?

3.  A baseball with a mass of 500 g is thrown at 12 m/s. What is the balls kinetic energy?

4.  A baseball thrown at 40 m/s has a kinetic energy of 64 J. What is its mass?

5.  What speed does a 1 kg mass have when its KE is 1 J?

6.  The kinetic energy of a golf ball is measured to be 143.3 J. If the golf ball has a mass of about 47 g, what is its speed?

7.  A biker takes 45 minutes to get from the top of a hill to the bottom. If the biker and bike have a total mass of 160 kg and they are moving at 9 m/s, what is their kinetic energy?

8.  The greatest speed that a meteoroid can have and still be pulled down to earth’s surface is 70 km/s. If a meteoroid traveling with this speed has a KE of 2.56 x 1013 J, what is its mass?

9.  A car is moving at 30 m/s and has a mass of 2000 kg and a truck is moving at 20 m/s and has a mass of 4000 kg. Which has more KE ? Show work.

Gravitational Potential Energy

1.  A 30 kg box is sitting on a shelf 3 meters high. What is its gPE?

2.  A ball has a potential energy of 150 J and a mass of 250 g. How high is the ball from the ground?

3.  A sky diver is about to jump out of a plane. The plane is 3 km high and the sky diver is 110 kg. What is the diver’s gPE?

4.  The world record for pole vaulting is 6.15 m. If the pole vaulter’s gravitational PE is 4942 J, what is his mass?

5.  A 75 kg person jumps off a 5 m high diving board. What is the person’s gravitational potential energy?

6.  In 1993, Cuban athelete Javier Sotomayor set the world record for the high jump. The gravitational potential energy associated with his jump was 1970 J. Sotomayor’s mass was 82.0 kg. How high did he jump?

Additional problems

1.  A 250 kg rock falls off a cliff and comes to rest on the ground which is 40 m below the cliff. At what point is the rock’s potential energy at a maximum?

  1. Where is its kinetic energy at maximum?

2.  The constant value for the speed of light (c) is 3 x 108 m/s. What is the mass equivalent of 100,000 J of energy? Use E = mc2.