## Saturday, July 17, 2021

### What is a Force, Types of Force, And Many More…..

Force can be feelable or invisible. It is a push or pull upon an object or it is an effort that can change the velocity or direction of an object, it can also change the shape. In today’s article, we will That what are the forces in physics.

We will also learn that how many types of forces are there in physics

There Are two types of forces.

We will also talk about other forces at the end of this article. But first, we need to understand these basic types of forces to understand other types of forces.

Contact force The force which is exerted by the object to object only by physical touching is known as the contact force.

e.g. When you kick a football it starts moving around the playground. You exert force by contacting the ball or by touching physically the ball.

Another example. When you go to a mall you apply a push force to open the gate. And then you grab the handle of the door and start pushing it so the door gets open.

Non-Contact Force Non-contact force is a force that applies force to any object without coming in contact. This means it does not touch physically or contact anything to apply the force.

e.g. A mango falls directly to the ground from a mango tree. That means the gravitational force attracts the mango to the ground without contacting anything.

Another example when you bring a magnet near an iron nail, you notice that the magnet attracts the nail toward itself. So it pulls the nail without contacting it or touching it physically.
The Unit of Force

The Unit force is Newton, Its symbol is ‘n’

The equation to find the Force is F=ma, where m is the mass of the body, and a is the acceleration of the body

How Many Types of forces

There are 9 types of forces in the world. Some of them are contact forces and some. of them are non-contact.
Contact forces
Friction force

Hey, do you ever think that why we lubricate the wheel of a bicycle with oil or with other kinds of lubricant?

Yes, you can understand the concept here. When the surface of an object roll or move over the surface of another object, a force is produced. this force works in opposite direction.

If you are rubbing an object in the north direction then the force will act in the south direction

It also helps to walk around the floor

A lubricant is used to reduce this frictional force. Now I think you have got that why we use oil to lubricate.

There are four types of lubricant which are used according to their need. Oil, Grease, Penetrating Lubricants, and Dry Lubricants. oil is the most common of all them we will also talk about lubricants and all about them but on another day. But for now, let’s get back to our topic.

Tension Force

Now, tension is a pulling force that is transmitted axially by the means of a string, a cable, chain, or similar one-dimensional continuous object, or by each end of a rod, truss member, or similar three-dimensional object.

e.g. Suppose a block is tied with a rope, and the rope is handed over to a person. When the person pulls the rope, tension gets built, and the rope gets taut.

On the further application of pull force, the box starts to overcome the frictional force and move in the direction of the force applied.

The person pulling the rope is not in direct contact with the block and is not able to transfer the force directly to the physical body.

The rope becomes a medium and the force reaches the block indirectly. Thereby, causing the block to move.

normal force

A normal force is a force exerted by the surface to prevent solid objects from passing through each other. it is equal to the force of gravity. The normal force is a contact force. know it sounds harder to learn. so let’s understand it with an example. let’s imagine, a book is kept on a table, as in the above picture, and now if you can see two types of force are acting on the book. gravitational force and normal force.

If the mass of the book is 10 kg then what will be the force acting on it. As we know F=ma where F= force, m=mass of the body/object, and a = acceleration so the mass we can take the mass of the book and that is 10 kg.

And the acceleration will 9.8. Because as we all know the gravity of the earth is 9.8. and it acts in the same quantity on everything.

So the force acting on the book will

F = 10×9.8 = 98n, Newton is the si unit of force, its symbol is ‘n’.

To prevent the book get to pass through the table. The surface of the table will exert a force that will be equal to the force of gravity.

So third law of motion is applied here. every action has an equal opposite direction. This exerted force will be called the normal force.

Air Resistance Force

hey, do you ever think that how the skydivers get to fly with a clothe in the air?

it is only possible, because of air resistance force

an air resistance force is a force that acts on an object when it passes through the air. It is a special type of frictional force. It often works in opposite direction.

If you found it harder to understand the let’s understand it with an example, otherwise you can skip this portion of the article.

imagine a skydiver dive into the sky and then suddenly he opened his parachute. After opening the parachute he got a force from the top which helps him to fly in the sky

two factors affect the air resistance.
Area of surface, as the area of surface increase, the air resistance will also increase
speed, as the speed of an object or air increase the air resistance will also increase

Applied Force

This force will be easy to understand, in simple words applied force is a force that is applied by any person /object or the force that is applied one object to another object is called applied force.

e.g. when you push the button on your keyboard.

Another Example. when you close your laptop. You pull it toward you to close it.

Spring Force

I think you often observe that when you compress a spring, it comes back to its original position. Do you ever think why it happens

let me explain that is because of spring force? this type of force is exerted when a spring is compressed or stretched and then the spring tries to get back in original its position.

The force that a spring applies to came back in its original state is called restoring force. You can also say that the spring force and the restoring force are equal, first observed by Robert hook.

But still, we can take a short recap here. here we needed the third law of motion, this law says that every action has an equal but opposite reaction. that means if you tap the table with your hand (Action) that will give you back in the same amount (Reaction)

The matter is the same here if you pull the spring (Action). The spring will give the same amount of force (Reaction) to come in its original position

Equation To Calculate Spring Force

the equation to find this force is F=-kx, where F is the restoring force,-k constant of spring, x is the displacement of spring.

if the constant of spring is in -/negative, the spring is compressed and it is pushing the object came in its original position, if it is in +/positive, the spring is stretched and it is pulling the object to come in its original position. Si unit of k is N/M.
let’s understand it with an activity imagine you have a spring, then you applied the force, the spring displaced 10 cm and the value of the constant is 5 N/M

That means firstly we need to convert cm to m, to convert cm to m we just need to divide the cm from 100

10÷100 = 0.1 m

therefore:

F = 5×0.1 = 0.5n

then you have applied more force and then the displacement is 20 cm

20÷100 = 0.2 m

Therefore:

F = 5×0.2 = 1n

Non-Contact Forces
Gravitational Force the object which has mass will also have gravitational force. the object which has more mass will also have more gravity, likely the earth has massive mass so it has a normal gravity.

Earth pulls everything on it even gases, this pull is known as the gravitational pull. It is an invisible force that pulls objects toward each other.

to find the force of gravity on any object we use F = ma, where F is force, m mass, and a is acceleration

Electric force An electric force is a force produced by atoms. this force inversely proportional to the charge of the atoms.

If the charge of one atom is negative and the charge of another one is also negative they will repel each other. If the charge is opposite to each other like one has positive and another one has negative then they will attract one another.

e.g. when you rub the mirror and bring it close to the small pieces of paper, the mirror attract them

we will also talk about it that hoe it happens

Magnetic force you must have played with magnets once in your life, But do you ever think that why it attracts iron?

Magnetic force is very similar to the electrical force but here the difference is moving particles in magnets. in electric force, the charges are stationary, which means they are not moving

Magnetic force can be described as the attraction or repulsion of the object from a magnet that is produced between electrically charged particles because of their motion.

magnets have a south pole and a north pole And they only attract objects which have freely moved electrons inside them like iron cobalt nickel

The force of magnet between the moving charges can make the effect exerted upon either charge by a magnetic field created by the other charged particles.