Aball at rest falls from a platform above the ground. the ball falls freely and hits the ground 1.1 s later. what is the height of the platform? 5.4 m 5.9 m 10.8 m 11.9 m

Correct option is (b)

Explanation:

Given a ball at rest falls from platform so initial velocity of the ball,

u =0

The ball hits the ground at time t = 1.1 s.

To calculate the height of the platform use equation of motion,

Here h is the height u is initial velocity of the ball t is time taken to hits the ground by ball and a is acceleration due to gravity and its .

Substitute the given values in above formula, we get

Thus, the height of platform is 5.9 m.  

f=ma a/f/m a= 480/60 a = 8m/s/s that is quick wow