A body of mass 2 kg is thrown up vertical

Your Ultimate Guide to JEE & NEET Question Solutions

A body of mass $2\, kg$ is thrown up vertically with K.E. of $490$  joules. If the acceleration due to gravity is $9.8$$m/{s^2}$, then the height at which the K.E. of the body becomes half its original value is given by ............ $\mathrm{m}$

A

$50 $

B

$12.5$

C

$25$

D

$10$

A body of mass $2\, kg$ is thrown up vertically with K.E. of $490$  joules. If the acceleration due to gravity is $9.8$$m/{s^2}$, then the height at which the K.E. of the body becomes half its original value is given by ............ $\mathrm{m}$

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
 $mgh = $ $\frac{{490}}{2}$

==> $2 \times 9.8 \times h = \frac{{490}}{2}$

==> $h = 12.5m.$