# A railroad freight car coasts along a level track. It collides and couples with a second car, initially at rest and with brakes released. What percentage of the freight car's initial energy is preserved in the two-coupled cars after collision?

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A railroad freight car, mass 15972 #kg# , is allowed to coast along a level track at speed 2 #m/s# . It collides and couples with a 41386 #kg# loaded second car, initially at rest and with brakes released. What percentage of the initial kinetic energy of the 15972 #kg# car is preserved in the two-coupled cars after collision?

A railroad freight car, mass 15972

##### 1 Answer

Nov 9, 2017

This is a Conservation of Momentum/Conservation of Energy question.