A student throws a small rubber ball vertically upward from ground level
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A student throws a small rubber ball vertically upward from ground level. Assume that air resistance is negligible and that the magnitude of acceleration due to gravity is 9.8m/s2.
(i) State a suitable sign convention that can be adopted for analysing the motion of the ball and briefly justify your choice.
(ii) Using the sign convention chosen in part (i), write the expressions for the velocity v(t) and the displacement s(t) of the ball as functions of time if its initial speed is 20m/s.
(iii) Determine the time at which the ball reaches its highest point and explain physically what happens to the velocity of the ball at that instant.