A ball of mass m is pushed down the wall of hemispherical bowl from point A. It just rises up to edge Q of the bowl. Find the speed at which ball is pushed down.

Explanation

From law of conservation of energy

Total energy at A = Total energy at Q
`(1)/(2)mv^(2)+mgh=0+mgR`
`(1)/(2)mv^(2)=mg(R-h)`
`therefore v^(2)=2g(R-h)`
or `v=sqrt(2g(R-h))`