When a hammer strikes a nail, it is compressed along its length. Suppose that a steel nail 9.00 cm long and 3.00 mm in diameter is compressed an average of 65.0 µm by a 0.490 kg hammer during a 1.20 ms collision.

Question

a) What is the average force exerted by the hammer on the nail?

I have tried to use F=ma and solve for a using dx/(dt)^2 (or dv/dt). When I entered 6.5e-5/(1.2e-3)^2 for acceleration and then multiplied the acceleration by .490kg, the answer was incorrect.