Suppose a cart is moving without any loss of energy to friction or air resistance. as the cart passes under a bridge, a heavy block is dropped vertically downward into the cart from a very small height above the cart. what happens to the speed of the cart

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.