Question

A ball is dropped from 215m. How long will it take to reach the ground? Use 9.8

Answer 1

Answer:

The time is  $t = 6.62 \ s$

Explanation:

From the question we are told that

   The height of the platform where the ball was dropped from is s  =  215 m

   The acceleration due to gravity is  $g = 9.8 \ m/s^2$

Generally from kinematic equations

     $s = ut + \frac{1}{2} gt^2$

Here u is the initial velocity of the ball and the value is  u = 0 m/s given that the ball was at rest before it was dropped

So

     $21 5 = 0 * t + \frac{1}{2} * 9.8t^2$

=>  $21 5 = 4.9t^2$

=>   $t^2 = \frac{215}{4.9}$

=>  $t = 6.62 \ s$