Heat and gravity are fundamental to the process
The energy source for plate tectonics is Earth's internal heat while the forces moving the plates are the “ridge push” and “slab pull” gravity forces.
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Pressure can be defined as the force acting on a perpendicular surface per unit area.
Force exerted by a man of mass 100 kg wearing snow shoes = m.a
Where m = mass of the man = 100 kg
a = acceleration due to gravity= 9.8 
Force exerted by the man of mass 100 kg = 
Force exerted by woman of mass 60 kg = 
Force exerted by 100 kg man is greater than that exerted as 60 kg woman. The area on which this force is acting determines the pressure. Pressure is inversely proportional to the area on which the force acts. Therefore, the pressure exerted by 100 kg man wearing snow shoes is less than the pressure exerted by a 60 kg woman woman wearing high heels as the force acts over a larger area when the man wears snow shoes when compared to the force exerted over a smaller area in case of the woman wearing high heels.