question_answer 19)

A batsman deflects a ball by an angle of 45° without changing its initial speed which is equal to . What is the impulse imparted to the ball ? Mass of the ball is 0.15 kg.  

Answer:

Speed of the ball    Let  and  be the velocities of the ball before and after deflection. As the speed of the ball remains unchanged even after deflection, so   In Fig. 5.130,  and . Clearly, the change in velocity of the ball is   Fig. 5.130   Then          Impulse imparted to the ball = Mass  Change in velocity of the ball   Impulse is imparted along . As the velocity  is the resultant of two velocities  and  which have equal magnitude, so  equally divides the angle between  and  i.e., impulse is directed along the bisector of initial and final directions.