Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

How would I calculate the deceleration of a vehicle (ATV), wheels locked, on dirt? How long would it take to halt? How fast is it decelerating?

I used this calculator, but it seems incorrect for a light vehicle.

share|cite|improve this question
^I might add that our vehicle is under 700lbs, and a max speed of 35mph. Also, according to that calculator, no matter what the mass, a vehicle going 35mph will stop in about 62 feet (.7 COF)...does that mean a train will stop in 62 feet as well? – Kevin Brown Mar 26 '12 at 20:24

The calculator assumes a constant coefficient of friction which is probably a good approximation within a certain range of weights for rubber tires on a hard surface. For a train, metal on dirt would probably have a very different coefficient of friction, and also the weight of the train would likely deform the surface, so this analysis would not apply. Likewise, for a vehicle stopping wheels locked on a soft dirt surface, there will be a digging in effect which will be different than stopping on asphalt.

share|cite|improve this answer
Before we start fights over this again, perhaps it would be better to call it the coefficient of rolling friction? – Alan Rominger Mar 27 '12 at 6:27
@AlanSE: The wheels are locked. – Ron Maimon May 26 '12 at 3:26
I don't see why the coefficient of friction model should work for dirt. You need to measure, it might be strongly velocity dependent. – Ron Maimon May 26 '12 at 3:28

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.