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Thanks!

**1. Homework Statement**

3) (a) Define the terms Work and Power. Derive an equation relating the power developed by an engine and the tractive force it produces. Note: ‘derive’ means show all working! [4]

The resistance to the motion of a car, Fr, of mass 2000 kg is proportional to its speed (i.e. Fr=kV). With the engine working at 72 kW the car can attain a maximum speed of 12 m/s when travelling up a straight hill inclined at and angle to the horizontal when sin = 0.1.

(b) Calculate the value of the resistive force and show that the value of k is

333.3 Ns/m. [6]

(c) Find the greatest speed at which the car could travel down the road with the engine working at 72 kW.

**2. Homework Equations**

work=force*distance

power=work/time

**3. The Attempt at a Solution**

Ive had a good look at this, and the only relationship that i am able to come up with in relation to both the work and power definitions is basically just

power=(force*distance)/time

I know that this statement is correct, but i just dont think that it is the correct answer for the question. And it seems that without this its not very easy to progess onto the next parts of the question.

Being quite honest, im not entirely sure what tractive force actually is, ive had a good look around google and not come up with much, and especially nothing in the way of a defintion.

So basically im stumped

Hope you can help

Thanks!