momentum word problem.... Problem: A tennis ball initially moves with a velocity of 30.0 m/s horizontally to the right. A tennis racket strikes the ball, giving it a velocity of 30.0 m/s to the left. Treat the collision as elastic and the ball and racket as particles of mass 0.0500= m1 kg and 0.500= m2 kg respectively. Find the initial velocity of the racket: My solution: I'm going to use the equation: Final (V) Ball = (m1 - m2) / (m1 + m2) * Ball(Vi) The racket is going some initial speed Vi... but because this equation requires that the second object , the racket, be stationary I will assign a new speed for the ball... 30 + Vi, then solve for Vi -30 = (0.0500 - 0.500)/( 0.0500 + 0.500) * (30 + Vi) -30/((0.0500 - 0.500)/( 0.0500 + 0.500)) - 30 = Vi = -6.66 m/s However the answer in the book is... -3.00.. Some help please..... thank you.