Question
Science Question on Inertia and Mass
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: (a) the net accelerating force and (b) the acceleration of the train.
Answer
(a) Net accelerating force = Force exerted by engine–Friction force (Here frictional force is subtracted because it opposes the motion) = 40000 –5000 = 35000 N = 3.5 × 104N
(b) From Newton's second law of motion, Accelerating force = Mass of the train × Acceleration of train a = F ---- m Mass of train = Mass of engine + Mass of all wagons = 8000 + 5 × 2000 = 8000 + 10000 = 18000 kg Acceleration = 35000 = 35 = 1.95ms-2