Home PHYSICS TOPIC 7: PRESSURE ~ PHYSICS FORM 1

# TOPIC 7: PRESSURE ~ PHYSICS FORM 1

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### Concept of Pressure

Pressure is defined as the force per unit area. OR Pressure is the force acting normally (perpendicularly) per unit surface area.

It is calculated by the formula:

Pressure = Force (f)/Area (A)

P = F/A

Where

• P – Pressure
• F – Force
• A – Area

The S.I Unit of Pressure

The SI unit of Pressure is Newton per square metre (N/M2). This unit is usually referred to as the Pascal (Pa).

1Pa = 1 N/M2

The other units of pressure are atmosphere, torr bar and mmHg.

1 atmosphere = 780mmHg

1 atmosphere = 1 105 N/M2 = 1bar (used by meteorologists)

Note: for a given amount of force, the smaller the area of application the greater the pressure exerted.

When a man lifts a bucket of water by its handle that is made with a thin metal, he would experience some discomfort but if the bucket was made with a thicker handle the discomfort will be much less if any.

This is because the area over which the force is applied is larger.