Question

A body of mass 2 kg is thrown up vertically with a kinetic energy 490J.If the acceleration due to gravity is 9.8m/s2, the height at which the kinetic energy of the body becomes half of original value is a)50m b)25m c)12.5 d)10

Answer 1

energy conservation

K1-K2 =mgh

490-490/2=2×9.8×h

490-245=19.6h

245=19.6h

h =245/19.6

h =12.5 m