Question

a ball is gentally dropped from a height of 20m if its velocity increase uniformely at the rate of 10m with what velocity will it strike the ground ?afterwhat time will it strike the ground

Answer 1

“Gently dropped” suggests that the initial velocity is zero.

The distance is 10m, and we know the acceleration to be 10m/s² too.

Hence, using the equation of motion:

v² = u² + 2aS

We get:

v² = 0² + 2 * 10 * 10 (m/s)²

v = 10√2 m/s

The final velocity is 10√2 m/s, or 14.14 m/s.

Now, to find the time, we use a form of the first equation of motion:

t = (v - u)/a

Or, t = (10√2 - 0)/10

Or, t = √2 s, or 1.414s