How do I calculate g-forces on a roller coaster?

[blackojacko]

Homework Statement

I have constructed a small scale roller coaster for my physics class. I was given the task of finding a track design with a safe and enjoyable ride. For times sake I plan to simply calculate the changes in g-force. I am using a hotwheels car and plastic track. I simply need to know how to go about calculating negative and positive vertical g-force.

Homework Equations

The few I have read about consist of the gravity constant and radius. Realistically radius might not be able to be obtained.

The Attempt at a Solution

I collected the mass of the car, and its acceleration throughout the track, but anything past data collection has not taken place.

 

[Simon Bridge]

The g-force is just the acceleration in units of 9.8m/s/s.
So work out the acceleration.

http://en.wikipedia.org/wiki/G-force

 

[blackojacko]

So convert the acceleration units?

 

[Simon Bridge]

Pretty much - remember the direction.
If you completely enclosed someone on a roller-coaster, they'd feel gravity change direction and strength.
That's what g-force is about.
Did you read the article?