A body of mass m, moving at velocity v, collides with a stationary body of the same mass and
sticks to it. The question asks for the the momentum and kinetic energy of the two bodies after the collision. My question is why the momentum is mv not 2mv ?

Question

A body of mass m, moving at velocity v, collides with a stationary body of the same mass and 
sticks to it. The question asks for the the momentum and kinetic energy of the two bodies after the collision. My question is why the momentum is mv not 2mv ?

anonymous · Answer

it depends on what type of collision it is..elastic or inelastic

anonymous · Answer

But the question doesn't mention anything else.

kmazraee · Answer

hey goutham! she said that STICK TO IT!

kmazraee · Answer

because the initial velocity of the stationary mass equals to zero! so : p=(m+m)v/2

anonymous · Answer

why is v/2 ?

kmazraee · Answer

m1v1+m2v2=(m1+m2)V so (m1+m2)V=m1v1 because of m1=m2 so V=v1/2      V is the final velocity of body that consist of two mass

kmazraee · Answer

notice that v2 is the initial velocity of stationary mass

anonymous · Answer

oh ok i got it thanks

kmazraee · Answer

ure wellcome!