1. The problem statement, all variables and given/known data a 120kg ball moving at 18m/s strikes a wall perpendicularly and rebounds straight back at 12m/s. after the initial contact, the centre of the ball moves 0.27cm closer to the wall. Assuming uniform deceleration, show that the time of the contact is 0.00075s. How large an average forced does the ball exert on the wall? i figure that: m=.12 u= 18 v=12 s1 - s2 = 0.0027 s1 = s2 + 0.0027 2. Relevant equations f= delta p/t = mv-mu/t s=ut+1/2at(squared) p=mv 3. The attempt at a solution what threw me off is the the time, i can get the average force no problem after i have the time. my question is do i put the time (0.00075) into the equation s=ut+1/2at(squared), because i have done that which worked out wrong. or do i rearrange and substitute some other formulas? if i dont have any formulas needed please tell me!