Pressure is defined as the force applied on an object per unit area of the object. Mathematically, pressure can be expressed as: Pressure = Force ( N ) Area ( m ² ) Since the unit for measuring force is Newton ( N ) and area is measured in square metres ( m ² ), the unit for pressure is N / m ² . The SI unit for measuring pressure is Pascal ( Pa ).

Gravitational force is an attractive force that acts between any two objects. The gravitational force between any object and the Earth acts as the weight of the object. The value of weight of an object depends on the acceleration due to gravity. Since, the value of the acceleration due to gravity is constant at all places on the Earth, the weight of an object charges with different places.