A stone is projected vertically up to reach maximum height h. The ratio of its kinetic energy to its potential energy, at a height `(4)/(5)`, will be

Options

A. `5:4`
B. `4:5`
C. `1:4`
D. `4:1`

Answer

(c)

Explanation

Total energy of the stone=mgh (Given)
Potential energy at a height of `(4)/(5)h=((4)/(5)h)mg=(4)/(5)mgh`
`K.E=mgh-(4)/(5)mgh=(1)/(5)mgh`
`(K.E)/(P.E)=(1//5mgh)/(4//5mgh)=(1)/(4)`
because `K.E:P.E=1:4`.