Question

A spherical ball of mass 20kg is stationary at the top of a hill of height 100m. it rolls down a smooth surface to a horizontal base at height of 20ma uniform cylinder of radius r and length l and mass m is lying on the ground with the curved surface touching the ground. if it is to be oriented on the ground with the flat circular end in contact with the ground the work to be done is

Answer 1

Answer:

Correct option is

A

40 ms

−1

For the potential energy, only the difference between the initial and final points count.

So this difference is 100−20=80 m

Conservation of energy

2

1

mv

2

=mgh

0.5v

2

=10×80

⇒v=40 m/s