Which statement about contour lines is true? a. they can never cross. b. they are always parallel. c. they indicate a flat area when drawn together. d. they signify where mineral deposits can be found.

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.