# Friction of a curved ramp

1. Nov 19, 2008

### GoSS190

I need to find the frictional forces and a snowboarder going off of a cuved jump. I know the coefficient of friction for the snow and the snowboarder is .05. The veolcity as the snowboarder is coming into the curved jump is:
sqrt(2(9.8*100*sin(theta))-(.05*9.8*100*cos(theta)))

I know the veolicty would have to do with centripetal motion but I dont know how to take friction into account to this because the normal force is always changing witht he curved surface.

2. Nov 20, 2008

### Hootenanny

Staff Emeritus
Are you asked to determine the frictional force at a specific point on the jump?

Could you perhaps post the complete question verbatim?

3. Nov 20, 2008

### GoSS190

well its not really a question that i have to solve. I am doing a project where I have to determing the distance a snowboarder will go. I have taken into account the friction forces for the hill but I dont know how to take into account the friction for the entire curve of the jump.

4. Nov 20, 2008

### nasu

You need to know the actual shape of the "curved" part. That will give you the normal direction for any point and you can calculate the normal force for any point. In general it's not very simple, you'll need to integrate along the curve.
Maybe you just approximate it with a segment of circle but still you need to know the initial and final angles of the circular segment and the radius.
Or even better, neglect the friction for the curved path or just estimate some average effect of the friction. You don't need to know the details of the motion if you only need the final speed.

5. Nov 20, 2008

### -Vitaly-

Suggestion, you can always fit a polynomial to a number of points. And intergate/differentiate it.
I did some couseworks at school about fricition, and numerical methods work really well for modelling real-time situation. Make some assumptions, do a simple model.
Then revise your assumptions, think which ones you can include in your model and improve it. And which ones are negligible and so on.