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 the ground and then climbs up another hill of height 30m and finally rolls down to a horizontal base at a height of 20m above the ground.The velocity attained by the ball is

Answer 1

First we will find its Ep.

We know,
Ep= mgh.
So, mgh 's formula is...
mgh = 1/2 mv ²
Hence, u = √ 2gh
Here u =√ 2 × 10 × 80
So right answer will be -- 40 ms ^-1