Question

A particle whose mass is 3 kg moves in the xy plane with velocity along the

line y=5.3 m.

(a) Find the angular momentum about the origin when the particle is at (12 m, 5.3 m).

(b) A force is applied to the particle. Find the torque about the origin due to

this force as the particle passes through the point (12 m, 5.3 m).

Answer 1

(a) The angular momentum:

$$L=pr=mvx=36v\text{ kg}·\text{m}^2/\text s.$$

(b) The torque:

$$T=Fd=12F\text{ N}.$$