# Physics

posted by
**Mary** on
.

A power boat of mass 475 kg is cruising at a constant speed of 8.9 m/s. The propeller provides a drive force of 770 N. The driver of the boat shuts off the engine, and the boat coasts to a halt. Assume -- contrary to fact -- that the resistive force due to the water is constant, independent of the boat's speed.

(a) How far does the boat coast?

(b) How much time does it take for the boat to come to rest after the engine is turned off?

friction force is 770N.

KEinitial=frictionforce*distance

solve for distance.

The average speed is 8.9/2 m/s. You know the distance

time=distance/avgspeed.