There's three balls on a smooth surface, A, B, and C, with masses m, 2m, and 3m respectively. Ball A is given a velocity u and collides elastically with B, which collides similarly with C.
I need to find the fraction of u that ball C has immediately after its impact with B.
I did the following:
0.5 * u^2 * m = 0.5 * ku^2 * 2m
1 = 2k
k = 1/2
Then:
0.5 * u^2/4 * 2m = 0.5 * ku^2 *3m
2(u^2)/4 = 3ku^2
1/2 = 3k
k = 1/6
Which I'm told I need to input as a decimal to 3 s.f. I typed in: 0.167 (no units) but it's wrong? Is my method wrong?