Question

If the energy of a ball falling from a height of 10 metres is reduced by 40%, how high will it rebound​

Answer 1

Answer:

Explanation:

Given :

If the energy of a ball falling from a height of 10 metres is reduced by 40%, how high will it rebound​

To find :

how high will it rebound​

Solution :

the ball is dropped from a height, h1 = 10

m

Potential energy at h1 = mgh1 Given g =10 m/s2, h1 = 10 m

Therefore the potential energy at h1 =

m×10×10

= 100m J

On striking the ground level, the ball looses 40% of its initial energy: i.e. (40/100)x 100m J

=40m J

he energy left on striking the ground =

100 m J-40 m J

= 60 m J

So the final energy of the ball, mgh2 =

60m J

i.e h2 = (60 /10) = 6 m

Hence the ball will bounce back to a height of 6 m