Chapter 11, Problem 32P

A particle is acted on by two torques about the origin: ${\stackrel{\to }{\tau }}_1$ has a magnitude of 2.0 N·m and is directed in the positive direction of the x axis, and ${\stackrel{\to }{\tau }}_2$ has a magnitude of 4.0 N·m and is directed in the negative direction of the y axis. In unit-vector notation, find $d\stackrel{\to }{\mathcal{l}}/dt$, where $\stackrel{\to }{\mathcal{l}}$ is the angular momentum of the particle about the origin.