Physics
posted by ABC .
On a frictionless table, a 3kg block moving 4m/s to the right collides with an 8kg block moving 1.5m/s to the left. If the blocks stick together, what is the final velocity? How much mechanical energy is dissipate in the collision?

+x to the right
initial momentum = 3*4  8*1.5 = 0
so final momentum = 0
so final velocity = 0
energy is all gone
Initial Ke = (1/2)(3)(16) + (1/2)(8)(2.25) 
Where do I find the answers?????