# How to model an accelerometer measurements on a car wheel?

I am working on kinematically modelling an accelerometer on a car wheel.

When working on the initial conditions, I am confused whether or not I should use the gravitational acceleration since there is a normal force reaction counteracting. I.e should a = [a0, 0 , -g]

Thanks for the help :) Yosef

My Go at it: What I was thinking of, is that in case I was modelling a point on the wheel, the gravity would not be considered. However when modelling the measurement of an accelerometer I should consider the acceleration. Probably I will need to shift to the equations of motions, which will make the whole story even more difficult.

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is the speed of the car changing? – Nic Nov 29 '11 at 16:23
What does the instrument read if you place in on the bench top? When you flip it over? Does that answer your question? – dmckee Nov 29 '11 at 16:26
Is this a homework problem? Also, what do you mean by "on a car wheel"? Where exactly is the accelerometer attached? – FrankH Nov 29 '11 at 17:04
Hey guys, thanks for asking. The accelerometer is attached on the tire at a radius r from the center of the wheel that is part of car. The car can be moving at a constant speed or accelerating. I doing my thesis on measuring the wheel's inclination while driving. – Yosef Nov 30 '11 at 10:54
Is it still vague? – Yosef Dec 1 '11 at 13:59