(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A railroad car of mass 27000 kg moving at 2.00 m/s collides and couples with two coupled railroad cars, each of the same mass as the single car and moving in the same direction at 1.20 m/s. (a) What is the speed of the three coupled cars after the collision?

2. Relevant equations

mv + mv = mv + mv

3. The attempt at a solution

Mrc = 27000 kg

Vrc = 2.00 m/s

M2rc = 54000 kg

V2rc = 1.20 m/s

(Mrc)(Vrc)i + (M2rc)(V2rc)i = (Mrc)(Vrc)f + (M2rc)(V2rc)f

(27000 kg)(2.00 m/s) + (54000 kg)(1.20 m/s) = (27000 kg)(0 m/s) + (54000 kg)(V2rc)f

V2rcf=2.20 m/s

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# Homework Help: Conservation of momentum railroad car collision

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