A body of mass 2 kg is thrown vertically with K.E. 490 J. Taking `g=10 m//s^(2)`. The height at which K.E. is reduced to half will be :

Options

A. 10 m
B. 12.25 m
C. 20 m
D. 25 m

Answer

b

Explanation

Loss in K.E= Gain in potential energy. ltvrgt `therefore mgh=(1)/(2)(490)=245`
`h=(245)/(2xx9.8)=12.25 m`