A 4.0-kg mass, initially at rest on a horizontal, frictionle…
A 4.0-kg mass, initially at rest on a horizontal, frictionless surface, is struck by a 2.0-kg mass moving along the x axis with a speed of 8.0 m/s. After the collision, the 2.0-kg mass has a speed of 4.0 m/s at an angle of 37° from the positive x axis. What is the speed of the 4.0-kg mass after the collision?