If a particle of mass 5.7 kg is moving east at 10 m/s and a particle of mass 19 kg is moving west at 10 m/s, what is the velocity of the center of mass of the pair? Give answer is m/s to the west.

Question

If a particle of mass 5.7 kg is moving east at 10 m/s and a particle of mass 19 kg is moving west at 10 m/s, what is the velocity of the center of mass of the pair?  Give answer is m/s to the west.

I tired to use: Vcm = mv/M.
I plugged in (5.7)(10) + (19)(10) / 5.7+19. = 57+190/24.7 = 10m/s.  This answer is wrong.  Please assist.

bobpursley · Answer

Of course it is wrong. Make E + direction, W - direction.

Angie · Answer

Thank you. I don't know why I was over looking that.

Daniel Araque · Answer

(19x10)-(5.7x10) / (19+5.7) = 5.38 m/s