Question

A body is thrown with a kinetic energy of 10j. If it attains a maximum height of 5m, find the mass of the body

Answer 1

According to question

Kinetic Energy with which the body is thrown

KE = 10 j

While going up the energy Changes to potential energy

Thus

PE =  10 J

We know 

PE = m * g * H

10  =  m * 10 * 5

m = 10 / 50

m  =  0.2 Kg

Thus  Mass of body is o.2 Kg

Answer 2

h=5
so,
$v = \sqrt{2gh}$
so v=10
kE=1/2mv square
10=1/2×m×10×10
m=0.2