1. The problem statement, all variables and given/known data It's the bottom of the ninth inning at a baseball game. Score is tied with a runner on 2nd when the batter gets a hit. The 85 kg runner rounds 3rd and is heading home with a speed of 8.0 m/s. Just before he reaches home plate he crashes into the catcher and the two players slide together along the base path toward home plate. Catcher's mass is 95kg. Coefficient of friction is 0.70. How far does the runner and catcher slide? 2. Relevant equations m1iv1i + m2iv2i = m1fv1f + m2fv2f 3. The attempt at a solution I found the velocity at which they slide together to be: m1iv1i +m2 = (m1 +m2)vf (85 kg)(8.0 m/s) + (95 kg) = (180 kg)vf 680 kg*m/s + 95 kg = 180 kg*vf vf = 4.3 m/s So now I have mass = 85+95 = 180 kg; vi = 4.3 m/s; vf = 0; u = 0.70 I don't know what to do next to find the displacement. The two equations I know to find x are: x=1/2(vf+vi)delta-t x=(vi)(delta-t)+1/2a(delta-t)^2 But I don't know t. I don't know a since I don't know t, unless I'm suppose to assume its constant. even with a=0 i still don't know t. please help!