A thin glass rod is a semicircle of radius R , see the figure(Figure 1) . A charge is nonuniformly distributed along the rod with a linear charge density given by ? = ? 0sin ? , where ? 0 is a positive constant. Point P is at the center of the semicircle.

Determine the magnitude of the acceleration of an electron placed at point P, assuming R = 1.8 cm and ? 0 = 1.7 ? C/m .

a = _____m/s^2

P +++++ R 0 * + X