Answer to Question #136017 in Mechanics | Relativity for Wonna Aung

Question

the car is parked on a muddy field and wheels of the car are sinking into the mud.
Explain why and how to prevent it

Answer 1

The mud is soft and viscous. When the wheel is rotating, the car will be deeper and deeper in mud. This happens because there is no grip. Car tries to get out of the muddy field, but instead it digs itself. Every piece of mud that was transferred from the front of the wheel to back of the wheel makes the hole for the wheel more shallow, but at the same moment other surrounding mud (or sand) comes to the same place. Car needs grip in order to start from the mud. There is no friction with the ground. Exactly friction makes car's wheels to displace.

To get out of the mud we can do:

1) lower pressure in the tyres, then they will have bigger surface.This will cause less pressure on the mud, the level of immersion into mud will be lower, and it will be easier to start.

2) Take any solid object that can be found nearby (rock, wooden stick etc) and put it before the wheel. As soon as car gets enough friction after the contact with the solid body, it starts to move.