Impulse-momentum theorem for constant force stopping

Steps:

• Net stopping force F = 92,000 N acts opposite to motion on mass m = 8 × 10⁴ kg = 80,000 kg.
• Deceleration a = F / m = 92,000 / 80,000 = 1.15 m/s².
• Change in velocity Δv = initial speed 14 m/s (final speed 0).
• Stopping time t = Δv / a = 14 / 1.15 ≈ 12 s.

Why A is correct:

• Calculated t ≈ 12 s matches 15 s as the closest option, using F = Δp / t from Newton's second law.

Why the others are wrong:

• B. 150 s requires a ≈ 0.093 m/s², or force ≈ 7,467 N—too small.
• C. 25 min (1,500 s) requires a ≈ 0.0093 m/s², or force ≈ 747 N—unrealistic for given thrust.
• D. 250 min (15,000 s) requires even smaller a ≈ 0.00093 m/s², or force ≈ 75 N—impossible.

Final answer: A