1. The problem statement, all variables and given/known data A 0.54kg ball falls from rest at a height of 26m and rebounds up 16m. If the contact between the ball and ground lasted 1.8ms, what average force was exerted on the ball? 2. Relevant equations F=ma v²=v0²+2a(x-x0) v=v0+at 1000ms=1s (1.8ms is 0.0018s) 3. The attempt at a solution (numbers are shortened for convenience but end results are with actual numbers) Calculated for velocity: v²=v0²+2a(x-x0) v²=0+2(9.8)(26) v=22.6m/s Calculated acceleration as ball hits ground: v=v0+at 0=22.6+a0.0018 a=12,541m/s² Calculate for force: F=ma F=(0.54)(12,541) F=6772.3N This is the answer I would try but it is wrong and I am missing something, like the 16m bounce up. I then tried to subtract the force calculated with the force exerted when the ball bounced back up, which had a force of: v²=v0²+2a(x-x0) v²=0+2(9.8)(16) v=17.7m/s v=v0+at 0=17.7+a0.0018 a=9838.2m/s² F=ma F=(0.54)(9838.2) F=5312.6N This is upward force so the resultant for is a downward (6772.3-5312.6)=1459.67N. This is also wrong and might have some assumptions in it. What is wrong with the calculations? Is there something that I didn't understand about the questions or the use of the equations?