Question Detail
Question
A 2500 kg body travelling at 40 km/h strikes a concrete wall and comes to rest in 0.2 s. What is the change in momentum?
Correct Answer
Option B is the correct answer.
Detailed Explanation
Convert 40 km/h to m/s: 40 × (1000/3600) = 40 × 0.2778 = 11.11 m/s. Initial momentum = 2500 × 11.11 = 27775 kg m/s ≈ 2.78 × 10⁴ kg m/s. Final momentum = 0. Change in momentum = 2.78 × 10⁴ kg m/s.
Hint
Δp = m(v_f - v_i).