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crash
08-14-2002, 10:05 PM
does anyone know of any equations for roller coaster designing that incorporates friction.

coasterguy1
08-15-2002, 03:34 PM
Well, Im thinking that is would be something like:

s+f+w=t, where "s" stands for speed without friction, "f" stands for friction, which would be a negative number, and "w" stands for wind resistance, another negative number. "t" is the total speed after all that is taken away. Of course, they would use it to tell how tall the next hill could be, but Im not sure what the next variable would have to be. Someone that has completed more of school (im a freshman this year, and Im taking Geometry. Just finished algebra in 8th grade) might be able to help on that.

condor27
08-15-2002, 04:38 PM
I think the only accurate way of finding out the friction coefficient of a rolling stock with respect to the track is experimentation.

I think the easiest way of doing that is by putting a train on very short straight track section, slightly inclined. At the higher end, the train is attached to a cable, and through a pulley, the other end of the cable is attached to a weight. The weight is adjusted so that the train isn't moving at all. That weight divided by the normal forces exerted by the train's weight is the static friction coefficient.

As for kinetic coefficient of friction, you can simply give the train a slight push so it moves. The weight is adjusted so that the train will not slow down or going faster. Then apply the same equation again, you have the coefficient of kintec friction.\

After you have the coefficient, you can simply multiply it with the train weight and number of vertical Gs (we engineers like to call that load factor) then you will have the actual friction force in pounds or Newton. When divided by the mass of the train, it will give you the deceleration of the train.

BimmerZ3
08-15-2002, 05:19 PM
Wow, if only I had a clue what the hell that meant.

coasterguy1
08-15-2002, 07:13 PM
I must be smart, I understand it all. I guess that IPC and Algebra class really did help. Amazing!

General Public
08-15-2002, 07:42 PM
Do you mean S-F-W=T, or did you just mean that the F and W figures would be negative? ;)

coasterguy1
08-15-2002, 09:27 PM
I knew they would be negative, so I put +, since that is what we usually do in class.

Jimmy B
08-17-2002, 01:39 PM
What, no calculus involved?!!! I always thought roller coaster physics involved rigorous higher-level math. I'm studying engineering physics in college and everything we're doing mostly math.

condor27
08-18-2002, 03:54 PM
Originally posted by Hurricane
What, no calculus involved?!!! I always thought roller coaster physics involved rigorous higher-level math. I'm studying engineering physics in college and everything we're doing mostly math.

No calculus for friction doesn't mean no calculus for roller coaster design. The equation for loop (plus properly designed turn as well) is a very complicated equation expressed in calculus.

http://mathworld.wolfram.com/CornuSpiral.html