Pressure

Pressure is defined as force acting per unit area. Its SI unit is Pascal or N/m². Its formula is Pressure: \(\frac{Thrust (F)}{Area (A)}\)

Thrust:

The force acting perpendicularly on a surface is called the thrust. It is a vector quantity. The SI unit is Newton (N).

One Pascal pressure:

One Pascal pressure is defined as the pressure exerted on a surface of area 1m²by the thrust of 1N.

Pressure depends on following factors:

• Thrust
• area

Proof of P = \(\frac{F}{A}\)

Let 'F' be the force acting perpendicularly, 'A' be the area and 'P' be the pressure exerted.

Then,

Pressure is directly proportional to the force acting perpendicularly.

Or, P ∝F.............................(i)

Pressure is inversely proportional to the area on which force acts.

P∝\(\frac{1}{A}\) .............................. (ii)

Combining equation (i) and (ii), we get

P∝\(\frac{F}{A}\)

or, P=K\(\frac{F}{A}\) [ where K is a constant ]

If 'F' is 1N, 'A' is 1m² and the pressure is 1N/m², then

K=1

so, P=\(\frac{F}{A}\)