Which of the following remains constant while throwing a ball upward?

Question

A body of mass 2 kg is moving with a velocity of 3 m/s. What is its kinetic energy?

Answer 1

Think of the ball's journey as two parts, going up and coming down.

Velocity: starts high, drops to zero at the top, then grows again in the downward direction. Not constant.
Displacement: keeps increasing while going up and then keeps changing as it falls back. Not constant.
Kinetic energy: since \(KE = \frac{1}{2}mv^2\), and speed changes throughout, KE also changes, dropping to zero at the highest point.
Acceleration: caused by gravity alone, it stays fixed at g, pointing downward, at every instant of the flight.

The only quantity that does not change during the whole trip is the acceleration. That makes option C the answer.

Answer 2

Think of the ball's journey as two parts, going up and coming down.

Velocity: starts high, drops to zero at the top, then grows again in the downward direction. Not constant.
Displacement: keeps increasing while going up and then keeps changing as it falls back. Not constant.
Kinetic energy: since \(KE = \frac{1}{2}mv^2\), and speed changes throughout, KE also changes, dropping to zero at the highest point.
Acceleration: caused by gravity alone, it stays fixed at g, pointing downward, at every instant of the flight.

The only quantity that does not change during the whole trip is the acceleration. That makes option C the answer.

Show Hint