# Homework Help: Kinetic Friction of jet powered skiis

1. Oct 3, 2007

### queenyv2005

1. The problem statement, all variables and given/known data
Joe, whose mass is 80kg, takes off across level snow in his jet powered skiis. The skiis have a thrust of 186N and a coefficient of kinetic friction on snow of 0.1. Unfortunately, the skiis run out of fuel after only 8 s. What is Joe's top speed? How far has Joe traveled when he finally coasts to a stop?

2. Relevant equations

3. The attempt at a solution

2. Oct 3, 2007

### Astronuc

Staff Emeritus

Joe's mass (80 kg) is subjected to a force 186 N, but experiences a retarding (friction) force. The coefficient of friction is 0.1.

So determine the acceleration, from which speed can be determined at the end of 8 s.

Then with that speed, Joe decelerates with friction, so determine how far based on the maximum speed (magnitude of velocity) through the distance where he stops.

Refer to this - http://hyperphysics.phy-astr.gsu.edu/hbase/mot.html

3. Oct 3, 2007

### queenyv2005

I got his top speed to be 10.76 m/s by using the frictional force in the equation. I just don't know which equation to use from there.