The concept of force and pressure

A force is a push or a pull of an object which changes a body state of rest into uniform motion. For instance a car at rest would begin to move if the engine is started and and set to accelerate. A ball position at rest would begin to move if kicked with the foot. A mango at rest by virtue of potential energy would be converted to kinetic energy when it begins to fall off from its tree.

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The unit for force is Newton(N) since it was discovered by Isaac Newton.

Mathematically, force is calculated by Mass of an objects by the product of it Acceleration due to gravity.

That's : Mass×Acceleration due to gravity.

M×g

Acceleration due to Gravity on Earth is Constant on Earth, that is 10m/s2 but keeps changing from planet to planet. They aren't the same when we move to another planet.

Work Examples:

1• Calculate the force acting on a mango with the mass of 20kg. Take Acceleration due to gravity to be 10m/s2.

Solution:

Force (F) = Mass × Gravity

F = M×g

Force (F) = 20kg × 10m/s2

Force (F) = 200N

2• A car in motion with the mass of 200kg, if the acceleration due to gravity is 10m/s2 calculate the force of the car.

Force (F) = Mass × Gravity

Force (F) = 200kg × 10m/s2

Force (F) = 2000N

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Types of Forces

There are so many types of Force. Examples of types of forces are:

1• Gravitational force
2• Frictional force
3• Tensional force
4• Magnetic force
5• Centrifugal force
6• Centripetal force
7• Electrostatic force
8• Surface Tension

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The concept of Pressure:

The pressure of on object is the force acting perpendicularly or normally on that object.

The unit for pressure is Newton metre square which is equivalent to Pascal.

Mathematically Pressure = Force ÷ Area

Pressure (P) = F/A

Where P = Pressure, F= Force and A= Area.

For instance, if the Force exerted per unit area is very high, the Pressure increases. So, Pressure is much depended on the large force acting on an area.

For example, two footwear are compared, High heel shoe and flat shoe wearing with 2 Ladies of the same Mass 80kg. The 2 Ladies were allowed to step on level ground after it had rained for few minute. The pointed toe of the high heel shoe was able to create a hole in the land while the flat shoe did not.

Reasons...

1• The toe of the high heel shoe was pointed so much force was exerted on the ground per very small area.

Much force, small surface area increases pressure.

2• The toe of the flat shoe was very large and flat, hence had very large surface to occupy. This exerted with low force which couldn't led the toe of the shoe to penetrate through the ground. So,no impact of the force was recorded.

Flat and wide surface objects exert small force per large surface area. Hence pressure is recorded.

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Work Examples
1• Calculate the pressure acting by high heel shoe on the ground with the force 100N, if the surface area it acts is 2m2

Solution:

Pressure = Force/Area

Pressure = 100N/2m2

Pressure = 50Nm2 = 50Pascal

2• Calculate the pressure of flat shoe acting on a ground with the force of 50N and a large surface area of 10m2

Solution:
Pressure = Force/Area

Pressure = 50N/10m2

Pressure = 5Nm2 = 5Pascal

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Comparing these two calculations, we saw that when much force was exerted, the pressure of the object increased per unit area. But when small force was exerted, the pressure of the object decreased per unit area.

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In our next meeting, we would delve into more details about force and pressure. Thanks for your attention.

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