Bogdan wrote:Rei I got another physics question if you come back on:
Block A (4kg)is moving is moving with velocity of (2m/s) and block b (8kg) is moving in the opposite direction with velocity of (3m/s) Which direction is the center of mass of the two block system moving?
A) 1 m/s in the same direction as b
B) 1.3 m/s in the same direction as b
C) 1.3 m/s in the same direction as A
D) 2.7 m/s in the same direction as A
E) 5 m/s in the same direction as A
Logically I can guess it's a or b. But I'm not sure what formula they use. The answer is B
So by the 2nd equation(ma*va+mb*vb)/(ma+mb) = (8 - 24)/(12) = -16/12 = -1.3m/s. That's by taking b as moving in the negative direction, so the COM is moving in the same direction as b.
Last edited by Rei Andros on Sat Dec 10, 2011 10:54 am; edited 1 time in total