A racquet ball with mass m = 0.225 kg is moving toward the wall at v = 15.4 m/s
ID: 2187310 • Letter: A
Question
A racquet ball with mass m = 0.225 kg is moving toward the wall at v = 15.4 m/s and at an angle of ? = 28.0? with respect to the horizontal. The ball makes a perfectly elastic collision with the solid, frictionless wall and rebounds at the same angle with respect to the horizontal. The ball is in contact with the wall for t = 0.079 s.
A racquet ball with mass m = 0.225 kg is moving toward the wall at v = 15.4 m/s and at an angle of ? = 28.0? with respect to the horizontal. The ball makes a perfectly elastic collision with the solid, frictionless wall and rebounds at the same angle with respect to the horizontal. The ball is in contact with the wall for t = 0.079 s. Now the racquet ball is moving straight toward the wall at a velocity of vi= 15.4 m/s. The ball makes an inelastic collision with the solid wall and leaves the wall in the opposite direction at vf= -10.5 m/s. The ball exerts the same average force on the ball as before. What is the magnitude of the change in momentum of the racquet ball?
Explanation / Answer
in the first case, change in momentum =( mvf- mvi )= m( vf cos x - vicos x ) x= 28 degrees. average force = Ft = mV = change in momentum F= MV/ t change in momentum =( mvf- mvi ) = 0.225( -10.5 - 15.4 ) = 5.82 cos 28 =5.14