Q 11-05-032NEETEAMCET 2007 (Medical)Easy
A body of mass $2$ kg is thrown up vertically with kinetic energy of $490$ J. If $g = 9.8\ \text{m/s}^2$, the height at which the kinetic energy of the body becomes half of the original value is
Answer: (C) $12.5$ m
Half the kinetic energy ($245$ J) has become potential energy:
$$mgh = 245 \;\Rightarrow\; h = \frac{245}{2 \times 9.8} = 12.5\ \text{m}$$
Solution by Sreeraj P, M.Sc Physics