Here is the problem that I need help with. I've done this sort of problem before, I just can't remember how to do it any more.

A ForceF1has a magnitude of 6.5 newtons in the same direction as the vector 3i - 4j - 12k. A second forceF2is 13 newtons in the same direction as the vector 7i + 24j + 60k.

Both forces are applied to a mass of 33.1kg at the same time. Find the acceleration of the mass due to the two forces applied.