Ball Collision Average Acceleration · PhysicsBowl 2010 #32

Physics · mechanics

Problem

A rubber ball of mass 2.0kg falling straight downward hits the ground with a speed of

0.90 \frac{\text{m}}{\text{s}}

and then rebounds straight upward with a speed of

0.60 \frac{\text{m}}{\text{s}}

. The collision time of the ball with the ground is

t = 0.25\text{s}

. Treat

g = 10 \frac{\text{m}}{\text{s}^2}

for this situation. What is the magnitude of the average acceleration (in units of

\frac{\text{m}}{\text{s}^2}

) of the ball while it is in contact with the ground? (A) 1.2 (B) 6.0 (C) 10.0 (D) 13.0 (E) 16.0