A ball is dropped from a height of 10 m. If the energy of the ball reduces by 40% after striking the ground, how much high can the ball bounce back? (g= 10 m s–2)
mgh = m× 10× 10 = 100mJ
Energy is reduced by 40% then the remaining energy is 60mJ.
Therefore, 60 m = m × 10 × h' or h' = 6m
