Hey hey! A 10g object moving to the right with a speed of 20cm/s makes an elastic head-on collision with a 15g object moving in the opposite direction with a speed of 30cm/s. Find the velocity of each object after the collision. So I have to come up with two equations and solve for unknown's simultaneously with plugged in values. That's one way of doing it. My solutions manual sucks at explaining the steps it took to get certain values, so I'm kind of lost on that. So you know I'm not just trying to get out of doing homework myself, this is what I tried: m1v1i + m2v2i = m1v1f + m2v2f (10g)(20m/s) + (-15g)(30m/s) = (10g)v1f + (15g)v2f -250 = 10v1f + 15v2f eq'n#(1) (10)(20) + (15)(30) = 10v1f + 15v2f 650 = 10v1f + 15v2f eq'n #(2) I think one of these isn't quite right because for 10g, I get -45cm/s when it's actually -40cm/s and for 15g, I get 30cm/s when it's only supposed to be 10cm/s. Could someone please point me in the right direction?