# Distance on a rollercoaster

1. Jun 8, 2005

### Frank_Horrigan

I am doing a project and one of the questions is to find the average force lost to friction. We measured a ball going down a "roller coaster" (it had 2 humps on it). WE have all the speeds and distances and accelerations, Now i calculated the energy lost to friction by taking the initial gravitational energy and subtracting the gravitational energy and kintetic energy after the first drop. So now I have the W in W=F x d but I cant figure out how to get the distance. Is there a way to calculate it or do I have to go measure it? It doesnt have a constant acceleration so I cant think of how I could calculate it.

2. Jun 8, 2005

### whozum

You can't really find the "force" lost to friction, since the force isnt conserved or anything nice like that. The energy lost to friction is a much nicer answer.

3. Jun 8, 2005

### NateTG

The friction also is very unlikely to be constant. If you want to figure out average friction, you might want to try using time. Getting the distance will involve measuring the track.

4. Jun 8, 2005

### Frank_Horrigan

Nate that is what im supposed to find, the Average force of friction. But I dont know what to do because dont i need a distance to use the equation W=F x d to solve for F?

I do have the times but i can not figure out how to encorporate them to find the average force of friction.

5. Jun 8, 2005

### NateTG

Well, if it's a physical experiment you should probably pull out the measuring tape.

6. Jun 10, 2005

### Chris Danger

What about using impulse, if you have the time and initial and final velocities? Then F(ave)*t = m*(Vf-Vi).