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?
1) 2.0 m/s
2) 2.7 m/s
3) 4.9 m/s
4) 2.4 m/s
5) 3.6 m/s
Answer: 2