posted by mangojuice .
Apparently, this website cannot display photos, so I'm gonna type my question:
A railway truck of mass 8340kg traveling at 14.3ms-1 collides with another truck of mass 6420kg traveling at 8.78ms-1 in the same direction.
1. If after collision the two trucks become joined together, what is their initial speed?
2.Calculate the percentage of kinetic energy retained in the collision.
please help I would be really grateful
8340(14.3)+6420(8.78) = (8340+6420)v
Ke initial = (1/2)(8340)(14.3^2) + (1/2)(8340)(8.78)^2
Ke final = (1/2)(8340+6420) v^2
it better be less.