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# Types of Forces

When an object is in motion state then it is in its current state either its motion or static state. If it is pulled or pushed then its position is changed. This external pushing or pulling the object which changes its current state of motion or static state is called force. The force is the exerted effect on the object which alters the condition of the object. It can be of different types that are contacted and non-contact force. It can be balanced and unbalanced force.

Thus, there are different types of forces like some contact forces are friction, tension, air resistance, etc. while some non-contact forces are gravitational force, electric force, and magnetic force. Let’s discuss more about different types of forces with some examples and their formulas.

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## Different Types of Forces

Force is a physical cause which changes the dimensions or the state of rest or the state of motion of a body.

Types of forces
Basically we can classify forces into four types :
1. Balanced force
2. Unbalanced force
3. Contact forces
4. Non contact forces

## Balanced Force

Force can be broadly divided into 2 categories :
1. Balanced Force
2. Unbalanced Force
Balanced force is when two equal and opposite forces are applied on a body in two exactly Opposite directions.

We can say that when some object is not moving then balanced forces are acting on that body. When equal and opposite forces act on a body, and the body does not move then it (body) is said to be in equilibrium.

Examples of Balanced Force
1. Soccer ball lying at rest on ground.
2. A helicopter positioned stationery in mid air : The weight of the helicopter acting downwards and the upward thrust of the engine of the helicopter are the two forces acting on the helicopter. The helicopter will remain stationery when these two forces are equal in magnitude but acting in opposite directions.

## Unbalanced Force

We know that when we stop pedaling a bicycle, the speed of the bicycle decreases due to friction, which is the only force acting against the bicycle. Thus, if the forces acting on a body produce any change in state of rest or motion, then the forces are said to be unbalanced. An unbalanced force, acting on an object, changes its speed or direction. The resultant of unbalanced forces is always greater than zero.

Examples of Unbalanced Force
1. Suppose the soccer ball, which was at rest, is now given a kick by a player, which means external force is exerted to upset the balanced forces. Hence, in this situation, the ball is under an unbalanced system of forces and the unbalanced force sets the ball in motion. Thus, it is an unbalanced force that changes the state of rest or motion of an object.
2. Similarly, in case of the helicopter, the unbalanced force can be created in two ways: The engine thrust upwards may be reduced so that only a part of the weight of the helicopter is balanced by this thrust and the remaining part of the weight of the helicopter becomes an unbalanced forced and that will influence the helicopter to move towards the ground.

## Frictional Forces

Let us first discuss what is friction. When you hit a ball and the ball is set into motion. But why does it stop after traveling a certain distance.

Newton’s first law says that,
An object continues to be at rest or continues to be in a motion unless it is acted upon by an external force. The external force in this case is nothing but the Frictional Force. In general, Frictional force is the opposing force acting on the body which resists the relative motion of the two bodies.
For example, when the ball moves along a surface, its motion is resisted, which means an action against the direction of motion is generated between the ball and the surface by the frictional force.

## Contact Force

As the name suggests, contact forces are such forces which are exerted on objects by direct contact. The forces which acts on bodies when they are in actual contact are called the contact forces.

The following forces come under Contact Forces.
1. Frictional forces
2. Normal reaction force
3. Tension force as applied through strings
4. Force exerted by a spring
5. Force exerted during collision
6. Force exerted by a spring
7. Force exerted during collision
8. Force applied as a pull or push
9. The kick on a soccer ball (in the above example) is a case of contact force. Because, the ball takes off only when a player kicks the ball by direct contact, thereby exerting a contact force. Most of the external forces are contact forces that set an object into motion.

## Non Contact Force

The forces which act on bodies without being physically touched, are called the non-contact forces.

The following forces come under non-contact forces :
1. Gravitational Force
2. Electrostatic Force
3. Magnetic Force

## Force of Gravity

We all know that gravity is something with which a body having larger mass attracts the another body which is having the lesser mass. g is the strength of the earth's gravitational field.
The Weight w of an object is proportional to its mass m, also relation between W and m is given by,
W = mgwhere,
g has a constant value in a particular place.

At the surface of the earth, if m is the mass in Kg then the value of g is 9.8 newton per kg, giving W in newtons.
The force acting on each and every kilogram is called the gravitational field strength and is given by the relation:

Gravitational field strength
, g = $\frac{force(weight)}{mass}$
g = $\frac{W}{m}$
where g = 9.8N/kg
 More topics in Types of Forces Balanced and Unbalanced Forces Contact Force Non Contact Force Friction
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