Momentum equals mass times velocity

Steps:

• Estimate typical family car mass as 1500 kg.
• Convert speed: 25 km/h = 25 × (5/18) ≈ 7 m/s.
• Compute momentum: p = 1500 kg × 7 m/s = 10,500 kg m/s ≈ 1 × 10^4 kg m/s.

Why A is correct:

• Momentum p = m v; 1500 kg car at 7 m/s yields ≈10^4 kg m/s, matching the order of magnitude.

Why the others are wrong:

• B: Underestimates by factor of 10; ignores realistic car mass.
• C: Overestimates by factor of 10; likely mistakes km/h for m/s.
• D: Far too low; equivalent to 100 kg at 10 m/s, not a car.

Final answer: A