Question

An axe that weighs 8.0 kg is used to strikes the log with a force of 400 N that comes

to rest in 0.04 seconds. What is the magnitude of the impulse? How fast is the axe approach the log?

Answer 1

The magnitude of impulse is

$$I=Ft=400·0.04=16\text{ kg m/s}.$$

The speed is

$$v=at=\frac Fmt=\frac{400}8·0.04=2\text{ m/s}.$$