Question Detail
Question
Two balls with equal mass are dropped from a height of 2 meters above the floor. They both bounce back up to a maximum height of 1.8 meters above the floor. The first ball is made of steel and is in contact with the floor for 0.04 seconds. The second ball is made of rubber and is in contact with the floor for 0.09 seconds. Which ball has a greater average force on the floor during the collision?
Correct Answer
Option B is the correct answer.
Detailed Explanation
Impulse = change in momentum = m(v_f - v_i). Both balls have same mass and same initial and final velocities (since same drop and rebound heights), so impulse is same. Average force = impulse / contact time. Steel ball has shorter contact time, so larger average force.
Hint
F_avg = Δp / Δt.