## Calculus (3rd Edition)

$16 \pi \ \mathrm{g}.$
We know that the mass density is $\frac{4}{r}$. Thus, the total mass of the plate is $$2 \pi \int_{0}^{2} r\left(\frac{4}{r}\right) d r=2 \pi \int_{0}^{2} 4 d r=16 \pi \ \mathrm{g}.$$