Given:

1hp = 746W

1 m/s = 2.237 mi/h.

When an automobile moves with constant velocity, the power developed in a certain engine is 66 hp. What total frictional force acts on the car at v = 50.8 mi/h? Answer in units of N.

Any hints on where to get started at least? This homework is due and our teacher hasn't gone over this yet so I'm kind of in the dark :\