An Object of Mass M₁ Is Moving with a Speed

Multiple Choice

An object of mass M₁ is moving with a speed v on a straight,level,frictionless track when it collides with another mass M₂ that is at rest on the track.After the collision,M₁ and M₂ stick together and move with a speed of

A) v
B) M₁v
C) (M₁ + M₂) v/M₁
D) M₁v/(M₁ + M₂)
E) M₁v/M₂