A body of mass `2 kg` is thrown up vertically with kinetic energy of `490 J`. If `g = 9.8m//s^(2)`, the height at which the kinetic energy of the body becomes half of the original value, is

Options

A. 50 m
B. 12.5 m
C. 25 m
D. 10 m

Answer

B

Explanation

Let h is that height at which the kinetic energy of the body becomes half its original value i.e. half of its kinetic energy will convert into potential energy
`therefore mgh = (490)/(2)rArr 2xx9.8xx h=(490)/(2)rArr h = 12.5 m`.