Question

A ball is thrown vertically upwards as shown. The ball reaches a height, H. What is the acceleration, 'a ' of the ball at point P?

(a)a = g
(b)a = -g
(c) a > g
(d) a = 0​

Answer 1

Acceleration of ball at point P is b) a = -g.

Let's see why :

• Let's assume but the ball was thrown vertically upwards with an initial velocity of u such that it reaches a maximum height of H.

Now, we know that:

• Along all points of the trajectory of the ball the object will experience a gravitational force which will be directed downwards towards the surface of the earth.

Now, since we have considered the initial velocity vector (directed upwards) to be positive, the gravitational force vector will be negative.

$\star$ b) a = -g is correct ✔️