A wooden block is at rest on a horizontal steel surface. If a 15.-Newton force applied parallel to the surface is required to keep the block in motion, how much force is required to start the block in
motion?
D) 15 N

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.