Calculating PE & KE

A 68 kg circus performer sits on a 4.2 m tall elephant. Find the potential energy of the performer.

• 2798.9 J

• 285.6 J

• 16.2 J

• 29.1 J

A 5 kg dog runs at 2.5 m/s. Find the kinetic energy of the dog.

• 6.25 J

• 12.5 J

• 15.6 J

• 122.5 J

Two bowling balls of equal mass are dropped from two different ledges. Ball B is dropped from twice the height of Ball A. How will their final kinetic energies compare immediately before they hit the ground?

• Ball B will have twice as much KE as ball A.

• Ball B will have four times as much KE as ball A.

• Ball B will have more KE by a factor of 2

• Ball B will have the same KE as ball A.

The skateboarder shown above has a potential energy of 2,800 J at a height of 4 meters. How much GPE and KE will she have when she is only 2 meters up?

• KE: 1000 J; PE: 1800 J

• KE: 1400 J; PE: 1400 J

• KE: 2800 J; PE: 0 J

• KE: 1400 J; PE: 0 J

Between a bowling ball and a soccer ball, which one has more kinetic energy and why?

• a bowling ball because it has more mass

• a bowling ball because it is smaller

• a soccer ball because it has more mass

• a soccer ball because it is smaller

A golf pro swings his driver with a mass of 0.75 kg at a velocity of 60 m/s. What is the kinetic energy of the club?

• 22.5 J

• It doesn't have kinetic energy-it has potential energy.

• 2,700 J

• 1,350 J

What is the mass of a ball has a kinetic energy of 450 J, what must it mass be if it is traveling through the air at 30 m/s?

• 0.25 kg

• 15 kg

• 1 kg

• 0.50 kg

A baby carriage sitting at the top of a hill is at a height of 21 m high. The carriage with the baby weighs 12 N. What kind of energy does the carriage have and how much?

• potential energy and 1.75 J

• potential energy and 252 J

• kinetic energy and 252 J

• kinetic energy and 1.75 J

Which of the following has the GREATEST IMPACT on the kinetic energy of an object and why?

• Mass because very small and very large things can't have the same kinetic energy.

• Velocity because its value is squared.

• Height because it can be a very large number.

• The acceleration due to gravity because it is acceleration which is more than velocity.

An 2 kg apple is hanging in a tree, 10 ft off the ground. What is the gravitational potential energy (gravity = 9.8 m/s²) of the apple?

• 960.4 J

• 98 J

• 1920.8 J

• 196 J