A train brakes from 30 m/s to rest in 15 seconds. If the mass of the train is 20,000 kg, the BRAKING FORCE is:
A40,000 N
B60,000 N
C30,000 N
D20,000 N
Answer & Solution
Correct answer: A. 40,000 N
Acceleration (deceleration) a = (0 − 30) / 15 = −2 m/s². Force F = ma = 20,000 × (−2) = −40,000 N. The negative sign indicates braking force (opposite to motion). Magnitude is 40,000 N (about the weight of 4 tonnes).
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