Question

A ball is falling from 600 meters. Find out the potential energy at 400 meters and also find out the kinetic energy when the ball was travelling half of the height and the mass of the ball is 20 kg

Answer 1

Answer:

ANSWER

Let a body of mass

′

m

′

placed at a height

′

h

′

above the ground, start falling down from rest.`

When the body falls from a height h to h/2, the potential energy is given as

2

mgh

.

The body covers the distance h/2 with a velocity v. We make use of the third equation of motion to obtain velocity of the body.

v

2

−u

2

=2aS

Here, u=0,a=g and S=x

v

2

−0=

2

2gh

,thatisv

2

=gh

Kinetic energy =

2

1

mv

2

That is, K.E=

2

mgh

Hence, at height h/2 the energy possessed is half potential energy and half the kinetic energy.