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.
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.