Given
$F(x, y) = x^2\mathbf{i} + xy\mathbf{j}$ $x^2 + y^2 = 49$
Find the work done by the force field on a particle that moves once around the circle oriented in the clockwise direction.
I've been using $ \int_C F(\vec{r}(t))\cdot \vec{r}'(t) dt $ to do other similar problem but usually $\vec{r}$ is given.