Three point charges are located on a circular arc as shown in the figure below. $($Let r $=3\mathrm{.}72$ cm$.$ Assume that the $+$x$-$axis is to the right and the $+$y$-$axis is up along the page.$)$

Three point charges lie on a circular arc, where the circle has center point P and radius r$.$

A charge of $2\mathrm{.}00$ nC is a distance r to the left of P$.$

A charge of $+3\mathrm{.}00$ nC is above and to the left of P by a distance r$,$ rotated up along the arc $30\mathrm{.}0\backslash$deg from the $2\mathrm{.}00$ nC charge.

A charge of $+3\mathrm{.}00$ nC is below and to the left of P by a distance r$,$ rotated down along the arc $30\mathrm{.}0\backslash$deg from the $2\mathrm{.}00$ nC charge.

$($a$)$ What is the total electric field at P$,$ the center of the arc? $($b$)$ Find the electric force that would be exerted on a $5\mathrm{.}26$ nC point charge placed at P$.$