The loop is in a magnetic field $0\mathrm{.}20$ T whose direction is perpendicular to the plane of the loop. At $t=0,$ the loop has area $A=0\mathrm{.}285m^2.$Suppose the radius of the elastic loop increases at a constant rate, $d\frac{r}{d}t=5\mathrm{.}45c\frac{m}{s}.$