Four railroad cars, each of mass 2.65104 kg, are coupled together and coastingalong horizontal tracks at speed vi toward thesouth. A very strong but foolish movie actor riding on the secondcar uncouples the front car and gives it a big push, increasing itsspeed to 4.05 m/s south. The remainingthree cars continue moving south, now at 2.30 m/s.
(a) Find the initial speed of the cars.
wrong check mark

(b) How much work did the actor do?
wrong check mark


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