Question

please help me with the 9th question

Answer 1

Mass (m) = 150g = 150/1000 kg = 0.15kg,initial velocity = 20m/s
Final velocity=-25m/s(direction of final velocity is opposite to that of initial velocity and so it is negative)
Time (t) = 0.01 seconds
change in momentum
deltaP = Pf - Pt =mv-mu = m(v-u)
=0.15(-25-20)
=[0.15×-45]kg m/s
=-6.75kg m/s
External force = deltaP/time
= -6.75/0.01
=-675N
Thus a force of 675 N is exerted on the ball by the batsman in the direction opposite to its original direction.