Question

3 kg stone falls from a height of 20 m height find the value of speed at 1o m height​

Answer 1

Speed of the stone just before touching the sand is

v=2gh=2×9.81×1000=140.07m/s

Deceleration of the stone due to sand is

v2−u2=−2as

0−140.072=−2(a)(2)

a=4905m/s2

We have initial speed and the deceleration, from

v=u−at

u=at

t=au=4905140.07=0.0285s