Question Detail
Question
Suppose you throw a ball with a mass of 0.40 kg against a brick wall. If it hits the wall moving horizontally to the left at 30 m/s and rebounds horizontally to the right at 20 m/s find the impulse of the net force on the ball during its collision with the wall.
Correct Answer
Option B is the correct answer.
Detailed Explanation
Impulse J = Δp = p_f - p_i. Take right as positive. Initial velocity = -30 m/s, final velocity = +20 m/s. J = (0.40 × 20) - (0.40 × -30) = 8 + 12 = 20 N.s.
Hint
Impulse equals change in momentum. Pay attention to the direction of velocities.