Objective type questions: Solution: Your response: ---- a b c d Start Over Cheat Mode

 Subjective type questions:

1. A train of mass 1000 kg is pulling two carriages, each of mass 300 kg, at a constant velocity, v. Given the engine produces a driving force of 6000 N and that there is a total resistive force of 3000 N draw the system diagram.

2. A box, of mass 2 kg, is on a horizontal desk. Draw the separated-body force diagram for the box.

3.A tug boat of mass 15000 kg is pulling four boats, each of mass 1500 kg, at a constant velocity, v. Given the engine produces a driving force of x N and that there is a total resistive force of y N, draw the system diagram.

Answers

1. Modelling the train and two carriages as a particle, the system diagram is shown below. Thus, the weight is the total of both the train and its carriages and the normal reaction (for the system) can be calculated from this. Both the driving force and resistive force are shown along with the velocity, v and the acceleration, a.

The diagram does not include the internal forces that would be included in a free body diagram, as they cancel each other out. For example the tension in the coupling between the train and its carriage cancels the tension between the same carriage and the train.

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