1. The problem statement, all variables and given/known data A golf ball of mass 41.8 g is dropped from a height h = 1.41 m onto a hard floor and bounces back to exactly that same height. What is the average force (in N) on the ball during the 0.012 s that it was in contact with the floor? 2. Relevant equations Impulse = Ft Impulse = m(Vf - Vi) 3. The attempt at a solution I am not quite sure how to proceed with this problem, becuase I am completely clueless as to how I should go about calculating the change in velocity, becuase if the ball returns to the same height, (no friction of air resistance) then arent the Vi and Vf both = 0?