Question

A body is projected vertically up.At a certain height h above ground its pe and ke ate in ratio 1:4.At what height from ground ratio of pe and ke will be 4:1

Answer 1

Given A body is projected vertically up.At a certain height h above ground its potential energy and kinetic energy are in ratio 1:4.At what height from ground ratio of potential energy and kinetic energy will be 4:1

Ratio is 1 : 4

Now P.E / K.E = 1/4

So 4 P.E = K.E

Let height h be in the ratio 4:1

Now K.E = P.E / 4

We know P. E + K.E = constant

P.E + K.E = P.E 1 + K.E 1

P.E + 4 P.E = P.E 1 + P.E 1 / 4

5 P.E = 5 / 4 P.E 1

5 mgh = 5/4 mgh 1 ( P.E = mgh)

h 1 = 4 h