Force needed to pull something from something liquid

[Lightsyn]

Hi... any idea on how to calculate force needed to pull up something stuck on the ground?
ex:
Boot stuck on mud
person sinking on quicksand
or car sinking in water

 

[mfb]

Depends on the situation. In general, there is no formula where you could just plug in numbers.

 

[Lightsyn]

What about a force diagram?
perhaps a way to calculate the force of the suction of mud?
does pressure has something to do with it?

 

[nasu]

Nothing simple and general. For materials like mud or quicksand the force may even depend on how fast you try to pull something out of it.