Question

A ball is thrown straight up in the air. For which situations are both the instantaneous velocity and the acceleration zero? (Select all that apply.)

Answer 1

The instantaneous velocity and acceleration of the ball thrown straight up in the air are both zero at point (b) at the top of its flight path.

When are the velocities zero

At this specific moment, the ball reaches its maximum height and momentarily stops before starting to descend. As the ball reaches the peak of its motion, its velocity becomes zero because it changes direction from moving upward to moving downward.

Simultaneously, the acceleration is also zero at the topmost point since the ball is momentarily at rest before gravity begins to pull it downward, causing acceleration due to gravity to act on the ball.

question

A ball is thrown straight up in the air. For which situation are both the instantaneous velocity and the acceleration zero? a) on the way up; b) at the top of its flight path; c) on the way down; d) halfway up and halfway down; or e) none of the above?

Answer 2

Therefore, the situation in which both the instantaneous velocity and acceleration become zero, is the situation when the ball reaches the highest point of its motion.

Step-by-step explanation:

When a ball is thrown upward under the free fall action of gravity, it starts to loose its Kinetic Energy as it moves upward. As the ball moves in upward direction, its kinetic energy gradually converts into its potential energy. As a result the speed of the ball starts to decrease as it moves up. Therefore, at the highest point during its motion, the velocity of ball becomes zero and it stops at the highest point for a moment, and then it starts to fall back down, under the influence of gravitational force.

Therefore, the situation in which both the instantaneous velocity and acceleration become zero, is the situation when the ball reaches the highest point of its motion.