Auniform wire with mass m and length l is bent into a semicircle. a. find the magnitude of the gravitational force this wire exerts on a point with mass m placed at the center of curvature of the semicircle.

The particle p starts from rest at point a at time t = 0 and changes its speed thereafter at a constant rate of 2.8g as it follows the horizontal path shown. determine the magnitude and direction of its total acceleration (a) just before point b, (b) just after point b, and (c) as it passes point c. state your directions relative to the x-axis shown (ccw positive) and choose the angle with the smallest magnitude.