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Question
A 8000 kg engine pulls a train of 5 wagons, each of 2000 kg. along a horizontal track. If the engine exerts a force of 40000 N and the track offers a friction force of 5000 N, then calculate:
- the net accelerating force and
- the acceleration of the train.
Solution
Mass of the rail engine = 8000 kg
Mass of five coaches = 2000 × 5
= 10000 kg
The force exerted by the engine = 40000 N
Friction force = 5000 N
a. Net acceleration force = Force applied by the engine – friction force
= 40000 − 5000
= 35000 N
b. Net force (F) = 35000 N
Total mass = 8000 + 10000
= 18000 kg
F = ma
35000 = 18000 × a
a = `35000/18000`
a = 1.9 m/s 2
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