A body of mass m, moving at velocity v, collides with a stationary body of the same mass and sticks to it.
The moment and kinetic energy of the two bodies after the collision are mv and 1/4mv^2 respectively.
i just don't understand why that is .. my working gives me a momentum of 2mv.
please help ?

Question

A body of mass m, moving at velocity v, collides with a stationary body of the same mass and sticks to it. 
The moment and kinetic energy of the two bodies after the collision are mv and 1/4mv^2 respectively. 
i just don't understand why that is .. my working gives me a momentum of 2mv. 
please help ?

anonymous · Answer

momentum and kinetic energy formulas are not the same.

anonymous · Answer

momentum is m*v

Kinetic energy is   1/2 mv^2