Question

5. An object is dropped from a height of 30m.If the energy of the object reduces by
55percent after reaching the ground, how much high can the object bounce back?(g =
10m/s)

Answer 1

Answer:

Given That The Ball Is Dropped From A Height,h

1

=10m

Potential Energy At h

1

=mgh

1

Therefore The Potential Energy At h

1

=m×10×10=100mJ

On striking the ground level, the ball looses 40%of its initial energy:

i.e.

100

40

×100mJ=40mJ

The energy left on striking the ground=100mJ−40mJ=60mJ

So the final energy of the ball, mgh

2

=60mJ

i.eh

2

=

10

60

=6m