Question

A ball is gently dropped from a height of 20 m. If its velocity increases uniformly at the rate of 10m s -2 , with what velocity will it strike the ground? After what time will it strike the Ground?

Answer 1

Height,h= 20m

"gently dropped" means initial velocity, u, =0m/s

Uniform acceleration, g=10m/s²

using the formula v²=u²+2gs

Substituting, v²=0²+2*10*20

v²=400

v=

`√(400)`

v=20m/s

Time, t at which is strike the ground

using the formula v=u+at

Substituting, 20=0+10t

20=10t

t=2s

This means that the bank strike the ground with a velocity of 20m/s in 2s.