L.c. smith shotguns book
12 2 In the figure above, block 1 with mass mı - 11 kg is initially at rest on a frictionless table that is pressed against a wall. Block 2 of mass m2 (my)/2 is placed between block 1 and the wall. It has constant speed v2 - 6 m/s. Assume the blocks collide elastically. The +x direction is pointing to the right.