In an elastic 1 -dimensional collision, a mass m1=3 kg with velocity v1 = -4 m/s collides with a mass m2 = 5kg at rest. What are the velocities v1' and v2' after the collision? I would like to your method of solving this problem. Thanks.

Answer 1

conserve momentum and KE before and after collision

(3)(-4) + (5)(0) = 3(v1)+5(v2)
(1/2)(3)(16) + (1/2)(5)(0) = (1/2)(3)(v1^2) + (1/2)(5)(v2^2)

v1 = 1
v2 = -3