A Particle of Mass M Moving at 5

Multiple Choice

A particle of mass m moving at 5.0 m/s in the positive x direction makes a glancing elastic collision with a particle of mass 2m that is at rest before the collision. After the collision, m moves off at an angle of 45^o to the x axis and 2m moves off at 60^o to the x axis. The speed of m after the collision is

A) 4.5 m/s.
B) 2.5 m/s.
C) 3.3 m/s.
D) 1.8 m/s.
E) 1.1 m/s.