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. 25 m
C. 12.5 m
D. 19.6 m

Answer

C

Explanation

At maximum height, kinetic energy converts into potential energy, i.e.
`U_("max")` = 490 J
suppose at height h., potential energy becomes half.
`implies mgh.=(U_("max"))/(2)`
Or h.=`(490)/(2xx2xx9.8)`=12.5 m