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A ball is thrown straight up into the air. At each of the following

instants, is the magnitude of the ball’s acceleration greater than g,

equal to g, less than g, or 0? Explain.

a. Just after leaving your hand.

b. At the very top (maximum height).

c. Just before hitting the ground.

Short Answer

Expert verified

a. The acceleration is equal to g, just after leaving your hand.

b. The acceleration is equal to g, at the very top (maximum height).

c. The acceleration is equal to g, just before hitting the ground.

Step by step solution

01

Part (a) Step 1: Introduction

If there is no other influence on a ball that is thrown upwards then the ball will move with a decreasing velocity and the acceleration remains constant.

02

Magnitude of acceleration

When a ball is thrown upwards, it has a positive velocity soon after it is leaving the hand. If we consider that there is no air resistance (which has a negligible influence on gravitation) then the ball should have an acceleration equal to the acceleration of gravity g.

03

Part (b) Step 1: Introduction

At the topmost position, the speed of the ball becomes zero.

04

Explanation

The speed of the ball gradually becomes zero at a peak point. As the influence of the earth on the ball is still the same and always remains constant, the acceleration of the ball at that point will be same as g.

05

Part (c) Step 1: Introduction

After reaching a certain height, the ball comes back to the ground. We have to discuss if the acceleration of the ball gets increased, reduced or remain the same.

06

Explanation

When the ball starts moving down the ground, still the acceleration remains constant as there is no air resistance on it mentioned in the question. Foe free fall, the acceleration is equal to the acceleration of gravity (g). So just before the ball hits the ground, its acceleration remains the same i.e. gravitational acceleration g.

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