1. The problem statement, all variables and given/known data We can use our results for head-on elastic collisions to analyze the recoil of the Earth when a ball bounces off a wall embedded in the Earth. Suppose a professional baseball pitcher hurls a baseball (m = 160 grams) with a speed (v1 = 44 m/s) at a wall, and the ball bounces back with little loss of kinetic energy. What is the recoil speed of the Earth (M = 6e24 kg)? 2. Relevant equations v=sqrt(2gh) p=mv p(total)=m1v1+m2v2 v=p/m 3. The attempt at a solution M(Earth)=6e24 kg M(Ball)=0.16 kg P(Ball) = 0.16*44 kg m/s = 7.04 kg.m/s The momentum must be the same before and after the collision. Therefore, the momentum provided to the Earth when the ball hits is 6.82 kg.m/s v(Earth) = P(total)/M(Earth+ball) v(Earth)=7.04/ 6e24 v(Earth)=1.173e-24 I was sure all my working was correct, but the answer is wrong. Is there anything I have missed?