Answer to Question #287737 in Physics for Rob

Question

An 80 kg man standing at rest on a smooth, level ice surface throws a 200 g ball horizontally with a speed of 25 m/s, relative to Earth.

(a) With what speed and in what direction does the man move? (3 marks)

(b) If the man throws six such balls every 5.0 s, what is the average force acting on him? (3 marks)

Answer 1

(a) The speed is

$$v=-25·0.2/80=0.0625\text{ m/s}.$$

The man moves backwards.

(b) The average force is

$$F=\dfrac{6·80·0.0625}{5}=6\text{ N}.$$