Question

A ball is gently dropped from a height of 20m. If its velocity increases uniformly at the rate of 10 m/s2 , with what velocity will it strike the ground? After what time will it strike the ground?

Answer 1

Explanation:

u =0, s =20 m, g = 10 m/s^2

as per equation of motion

v^2 = u^2 + 2*g*s

v^2 = 0 + 2*10*20 = 400

taking square root

v = 20 m/s

hence the velocity with which the ball will strike the ground is 20 m/s

time t =(v - u)/g = 20/10 = 2 sec

the ball will strike the ground after 2 sec

Answer 2

Explanation:

here the short way to find the time