the formula is actually: [1/2m1v1i^2 + 1/2 m2v2i^2 = 1/2m1v1f^2 + 1/2m2v2f^2] for a) and b) ,for c) i used [m*a = -u*m*g] and [vf^2 = vi^2 + 2*a*d] ,i got 4.67m/s for a) 2.319m/s for b) and 4.82 m for c) , i know a) is right but i don't have the answers for b) and c) so i want to make sure i...