A ball of mass 0.15 kg is dropped from a height 10 m, strikes the ground and rebounds to the same height. The magnitude of impulse imparted to the ball is (g=10 m/s2) nearly : (1) 1.4 kg m/s (2) 0 kg m/s (3) 4.2 kg m/s (4) 2.1 kg m/s
Velocity while hitting the ground v=√2×10×10=10√2 As it goes to the same height it will return with same speed. So change in velocity v−(−v)=2v Change in momentum or impulse =2mv =2×0.15×10√2 =3√2=4.2kgm/s
