Chapter 6, Problem 36A

What is the acceleration of a rock at the top of its trajectory when thrown straight upward? Explain whether or not the answer is zero by using the equation $a=F/m$ as a guide to your thinking.

To determine

The acceleration of the rock at the top of its trajectory when thrown straight upward.

Answer to Problem 36A

At the top of the trajectory, acceleration acting on the rock is the acceleration due to gravity.

Explanation of Solution

Introduction:

The acceleration due to gravity always acts on every object in vertically downwards direction.

When a rock is thrown straight upwards, then gravity will always acts on it in downward direction. Thus, though at the top of its trajectory, the rock will come to a momentarily rest but still gravitational force and thereby the acceleration due to gravity will act on it.

Conclusion:

Hence, the acceleration acting on the rock at the top of its trajectory is due the acceleration due to gravity.