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(a) the net accelerating force
(b) the acceleration of the train
(c) the force of wagon 1 on wagon 2.
Answer :
(a) Given, force exerted by the train (F) = 40,000 N
Friction exerts a force of = -5000 N {the negative sign indicates that the force is applied in the opposite direction}
\(\therefore \) The net accelerating force = sum of all forces = 40,000 + (-5000 ) = 35,000 N
(b) Total mass of the train = mass of engine + mass of each wagon = 8000 + 5 × 2000 = 18000 kg
We know that, F = ma \( \Rightarrow a = \frac{F}{m} \)
Therefore, acceleration of the train = (net accelerating force) / (total mass of the train)
\( \Rightarrow \frac{35,000}{18,000} = 1.94 m/s^2 \)
(c) Force of wagon 1 on 2 = mass of 4 wagons × acceleration
\( \Rightarrow F_{1,2} = 4 × 2000 × 1.94 \ \Rightarrow \ F = 1552 N \)