Chapter 11, Problem 23P

Force $\stackrel{\to }{F}=\left(2.0\text{N}\right)\hat{i}-\left(\text{3}\text{.0}\text{N}\right)\hat{k}$ acts on a pebble with position vector $\stackrel{\to }{r}=\left(0.50\text{m}\right)\hat{j}-\left(2.0\text{m}\right)\hat{k}$ relative to the origin. In unit-vector notation, what is the resulting torque on the pebble about (a) the origin and (b) the point (2.0 m, 0, −3.0 m)?