# Need help with a problem

1. Sep 19, 2006

### Super King

A snowboarder descends a hill with an incline of 50°. the coefficient of kinetic friction of the board on the snow is µ = 0.100. The mass of the snowboarder and board is 86 kg. The snowboarder starts at rest and ends up 390 meters down the slope. (a) What is the work done on the snowboarder by the force of friction (watch sign)? (b) What is the boarder's speed at the end of the course?

Can anyone help me with this problem. I appreciate it.

2. Sep 19, 2006

### Hootenanny

Staff Emeritus
Welcome to the Forums,

One is expected to show one's efforts before asking for help.

HINT: Work - energy theorem

3. Sep 19, 2006

### fatra2

a) -2.11 x 10^4 J
b) 73m/s or 264km/h

4. Sep 19, 2006

### Hootenanny

Staff Emeritus
Please do not post answers, although they are correct (you second answer is off by 3 m/s); the OP learns nothing of the method. It is better to allow the poster to attempt their question then correct their method by guiding them to the correct answer.

Last edited: Sep 19, 2006
5. Sep 19, 2006

### fatra2

Hi there,

I fully agree that giving out the complete answer is certainly not helping. I thought that having the final answer can be quite helpful in solving the problem. You can double check that you have the correct solution to the problem.

6. Sep 19, 2006

### Hootenanny

Staff Emeritus
Although I do agree with you, it can be useful to have an answer to work towards; it is the policy of this forum not give out answers since some 'unscrupulous' students may just copy down the answers without every really understanding the subject matter.

Your help is appreciated though, as you can see there are a lot of questions posted in the homework forums and any one willing to help is much appreciated and I hope you will continue to do so.