Contact and Non Contact Force - Definition, Examples, Types, Difference, FAQs

Edited By Vishal kumar | Updated on Nov 18, 2024 03:53 PM IST

Have you ever tried to push a door open or felt gravity pull you the moment you jumped? These are the Forces we encounter in our daily lives. Push or pull is a force that changes or motions or shape of an object. This article will focus on the definition, types, and examples of contact forces and non-contact forces. In addition, we will learn how they affect the motion and behavior of objects around us.

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Define Contact Force
Define Non-Contact Force
Difference Between Contact and Non-Contact Forces

Contact and Non Contact Force - Definition, Examples, Types, Difference, FAQs

Define Contact Force

Contact Force is defined is the Force that comes into contact with another object. A force that only functions when two bodies come into physical touch. These force act on the point of contact and results in pushing, pulling, or friction.

Magnitude of Contact Force:

To determine the magnitude of contact force, first, we have to identify the nature of interaction between the objects. Now let's discuss the different scenarios to calculate the magnitude of contact force:

Contact Force on a Stationary Object

If the object is placed on a normal flat surface, then contact force will become equal to the normal force.

$$
F_{\text {contact }}=F_{\text {normal }}=m g
$$

where:
$m$ : Mass of the object
$g$ : Acceleration due to gravity $\left(9.8 \mathrm{~m} / \mathrm{s}^2\right)$

Contact Force on an Object on an Inclined Plane

If an object is placed on an inclined surface then the magnitude of contact force will be equal to the vector sum of normal force and frictional force.

$$
F_{\text {contact }}=\sqrt{F_{\text {normal }}^2+F_{\text {friction }}^2}
$$

$F_{\text {normal }}=m g \cos \theta$
$F_{\text {friction }}=\mu F_{\text {normal }}=\mu m g \cos \theta$
( $\mu$ : Coefficient of friction, $\theta$ : Angle of the incline)

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Types of Contact Force

Contact forces can be classified into different types. Let's look at these types in brief :

Frictional Force: Force that opposes relative motion between two surfaces in contact.
Normal Force: A surface force perpendicular to an object in contact with that surface.
Tension Force: If you pull a string, rope or cable tight, you send a force through it.
Applied Force: The force applied by one person or object to another person or object.
Spring Force: The force exerted by a compressed or stretched spring on that object attached to it.

Examples of Contact Forces

When you stretch the spring out of its resting state, it will begin to oscillate from its mean position. The spring, however, returns to its original position after a period of time due to the influence of restoring force.

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Define Non-Contact Force

A force applied to an object by a body that is not in direct touch with it is known as a non-contact force. When objects do not make physical touch with one another or when a force is exerted without interaction, non-contact forces are at work.

Types of Non-Contact forces:

Different types of Non-contact forces are listed below:

Gravitational Force- The force of attraction between two objects due to their masses. It acts over a distance and depends on the mass of the objects and the distance between them.

Electrostatic Force- The attraction or repulsion of any charged objects. Like charges repel and unlike charges attract.

Magnetic Force- Force experienced by a magnet when placed in a magnetic field.

Nuclear Force- Nuclear force is furthur divided into two types:

Strong Nuclear Force- The force that keeps the protons and neutrons together in the nucleus of an atom.

Weak Nuclear Forces- Responsible for issues like radioactive decay and certain nuclear reactions.

Examples of non-contact forces:

Example 1:

Electricity is generated in your home by an invisible force acting on electrons travelling through the wiring of your equipment. Do you have any idea how it happens?

The flow of electrons in a wire is caused by the electric force, which contains millions of electrons in random motion.

Example 2:

Let's say you tied a wire around an iron nail, and when you supply current, a magnetic field forms around it. Do you have any idea why this happens? When current flows over a wire, millions of electrons make random motions, and these random electrons align in the desired direction, resulting in the formation of a magnetic field.

Now, under the influence of magnetic force, or attraction force, iron filings are drawn to the iron nail (or a magnet).

Difference Between Contact and Non-Contact Forces

Contact force	Non-contact force
Only when there is a physical effort (push or pull) on an object can the forces act.	These forces are invisible by nature and can act without requiring any physical effort.
Vector fields can be used to depict contact forces.	Non-contact forces cannot be represented using vector fields
The contact force is not linked with any field.	The non-contact force is related with a particular field.
Because of the friction between two palms, friction between two bodies in contact, such as rubbing palms, produces heat.	Because of gravity, a ball that is soaring in the sky will eventually fall to the ground.
Example- When the bus abruptly stops, a dozing man awakens.	Example- When you combine the North poles of two magnets, you'll see that they repel each other. When you change the direction of one of the magnets, you'll notice that they attract each other.

Frequently Asked Questions (FAQs)

1. Differentiate between contact and non-contact forces.

A contact force is a force that acts between two bodies in contact. For example, the contact force is created when you push a table against the wall or when you pull anything upwards since there is direct touch between you and the object you are pulling. Between bodies that are not in direct contact, a non-contact force acts. An apple, for example, fell on Newton due to the unseen force of gravity.

2. Define contact force.

Contact Force is defined as the force that comes into contact with another object.

A force that only functions when two bodies come into physical touch.

Newton's second law of motion was discussed. It claims that applying force to a body of mass ‘m' causes it to accelerate

If the mass of the body is ‘m,' and the acceleration it achieves after being subjected to force is ‘a,' then the force equation is:

F = ma

3. What are the different types of non-contact force?

Non-contact forces are listed below:

The force of gravity
The combination of electric force and magnetic force commonly referred to as Electromagnetic force
Nuclear force

4. Give examples of a non-contact force?

The force that does not make contact. Non-contact or action-at-a-distance forces include magnetism. These are forces that can act on an object even if they are not physically touching it. Another example is the force of gravity. As a result, gravity will pull a raindrop down to Earth despite the fact that there is no physical connection between the Earth and the drop.

5. Is tension a force that does not make contact?

The forces that emerge from the interaction of objects that come into contact with each other are known as contact forces. Friction, air resistance, applied force, tension force, and spring force are examples of these. Non-contact forces are produced by the interaction of objects that are not in direct contact with one another.