Question Detail
Question
A 6.0 × 10⁻² kg tennis ball moves at a speed of 12 m/s. The ball is struck by a racket, causing it to rebound in the opposite direction at a speed of 18 m/s. What is the change in the ball's momentum in kg m/s?
Correct Answer
Option B is the correct answer.
Detailed Explanation
Take initial direction as positive. Then p_i = 0.06 × 12 = 0.72 kg m/s. p_f = 0.06 × (-18) = -1.08 kg m/s. Change = p_f - p_i = -1.08 - 0.72 = -1.8 kg m/s. Magnitude = 1.8 kg m/s.
Hint
Δp = m(v_f - v_i), watch signs.