Question

A 5kg stone is dropped from the top of a 1000 m high tower. If it penetrate the sand 2 m deep . Find the time to penetrate.​

Answer 1

Answer:

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

v

2

−u

2

=−2as

0−140.07

2

=−2(a)(2)

a=4905m/s

2

We have initial speed and the deceleration, from

v=u−at

u=at

t=

a

u

=

4905

140.07

=0.0285s