At what position does a moving object have the most kinetic energy?

At what position does a moving object have the most kinetic energy?

• A. Resting at the top
• B. Traveling up the hill
• C. Traveling down the hill
• D. Traveling at the bottom

Answer: (D)

Kinetic energy depends on how fast the object is moving: KE = 1/2 m v^2. On a hill, gravity converts potential energy into kinetic energy as the object descends. As it goes down, it speeds up, so its kinetic energy increases. At the bottom, height is lowest and speed is greatest, so the kinetic energy is at its maximum. At the top, if it’s momentarily at rest, KE is zero; moving up means it slows down, reducing KE. Thus the greatest kinetic energy occurs at the bottom of the hill. (If there were friction, some energy would be lost as heat, but the bottom would still have the largest KE among these positions.)

Kinetic energy depends on how fast the object is moving: KE = 1/2 m v^2. On a hill, gravity converts potential energy into kinetic energy as the object descends. As it goes down, it speeds up, so its kinetic energy increases. At the bottom, height is lowest and speed is greatest, so the kinetic energy is at its maximum. At the top, if it’s momentarily at rest, KE is zero; moving up means it slows down, reducing KE. Thus the greatest kinetic energy occurs at the bottom of the hill. (If there were friction, some energy would be lost as heat, but the bottom would still have the largest KE among these positions.)