- #1
Eugbug
- 21
- 0
If a body of mass m and velocity u collides with another body of mass m which is stationary,
and then the two bodies move off together, then conservation of momentum suggests that the since the combined mass is 2m, the new velocity will be 1/2 u.
Total momentum before collision = mu + m0 = mu
Total momentum after collision = m(1/2u) + m(1/2u) = mu
However energy before collision = 1/2mu2
and energy after collision = 1/2m(1/2u)2 + 1/2m(1/2u)2 = 1/4mu2
So it seems the energy is halved or am I making an error in the calculations ?
and then the two bodies move off together, then conservation of momentum suggests that the since the combined mass is 2m, the new velocity will be 1/2 u.
Total momentum before collision = mu + m0 = mu
Total momentum after collision = m(1/2u) + m(1/2u) = mu
However energy before collision = 1/2mu2
and energy after collision = 1/2m(1/2u)2 + 1/2m(1/2u)2 = 1/4mu2
So it seems the energy is halved or am I making an error in the calculations ?