Because
1: p_i = p_f
2: (3kg)(5.9m/s) = 3v_1_f + v_2_f
And, in an elastic collision
3: v_1_i - v_2_i = -v_1_f + v_2_f
4: 5.9m/s - 0m/s = -v_1_f + v_2_f
5: 5.9m/s + v_1_f = v_2_f
Now I replaced the v_2_f in line 2 with the work in line 5.
6: (3kg)(5.9m/s) = 3v_1_f +...
I don't assume anything. I got that the speed of the first ball after the collision is 2.95 m/s and the speed of the second is 8.9 m/s. I just don't know whether or not my numbers are correct.
As much as I hate to bump threads...
I thought this was a simple problem, but does no one know for sure? I'm pretty sure between 3.9 and 4.05 is right, I just need some verification, because no one else got what I got.
I had this problem on a quiz today and I got 4.05m. I'm not sure if this is right though, can anyone verify this?
A 3kg ball is situated on a bent frictionless wire at A as shown below (I hope this shows up) and a 1 kg ball is situated at B. After the two balls collide, how far does ball B...