Pressure

Pressure is the force exerted per unit area on the surface of an object. It is a fundamental concept in physics and is measured in units such as pascals (Pa) in the International System of Units (SI). Pressure can be exerted by gases, liquids, or solids and acts perpendicular to the surface it is applied to. For example, when you inflate a balloon, the air inside exerts pressure on the balloonβs walls, causing it to expand. Similarly, atmospheric pressure is the weight of the Earthβs atmosphere pressing down on everything at the surface. Pressure is essential in various applications, from understanding weather patterns and fluid dynamics to designing hydraulic systems and studying the behavior of gases.

Contents

Practice problems

Problem #1

Calculate the pressure acting on a disc with a surface area of 5 m2 when a force of 50 N is exerted on it.

Solution

Given data:

• Pressure acting on a disc, P = ?
• Surface area of a disc, A = 5 m2
• Force exerted on a disc, F = 50 N

Applying the formula:

• P = F/A
• P = 50/5
• P = 10 N/m2

Therefore, the pressure acting on a disc is 10 N/m2.

Problem #2

If a 10 N force is exerted on a box with a surface area of 2 m2, what is the value of the pressure acting on the box?

Solution

Given data:

• Force exerted on a box, F = 10 N
• Surface area of a box, A = 2 m2
• Pressure acting on a box, P = ?

Applying the formula:

• P = F/A
• P = 10/2
• P = 5 N/m2

Therefore, the pressure acting on a box is 5 N/m2.

Problem #3

A boy exerts a force of 28 N on a flat plate with a surface area of 4 m2. Calculate the pressure acting on the flat plate.

Solution

Given data:

• Force exerted on the flat plate, F = 28 N
• Surface area of the flat plate, A = 4 m2
• Pressure acting on the flat plate, P = ?

Applying the formula:

• P = F/A
• P = 28/4
• P = 7 N/m2

Therefore, the pressure acting on the flat plate is 7 N/m2.

Problem #4

A drummer exerts a force of 18 N on a drum head with a drumstick. If the surface area of the drum head is 3 m2, calculate the pressure acting on the drum head.

Solution

Given data:

• Force exerted on a drum head, F = 18 N
• Surface area of a drum head, A = 3 m2
• Pressure acting on a drum head, P = ?

Applying the formula:

• P = F/A
• P = 18/3
• P = 6 N/m2

Therefore, the pressure acting on a drum head is 6 N/m2.