• Engineering and Architecture
  • Management and Business Administration
  • Medicine and Allied Sciences
  • Law
  • Animation and Design
  • Media, Mass Communication and Journalism
  • Finance & Accounts
  • Computer Application and IT
  • Pharmacy
  • Hospitality and Tourism
  • Competition
  • School
  • Study Abroad
  • Arts, Commerce & Sciences
  • Learn
  • Online Courses and Certifications
Contact and Non Contact Force - Definition, Examples, Types, Difference, FAQs

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

Vishal kumarUpdated on 02 Jul 2025, 05:08 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.

This Story also Contains

  1. Define Contact Force
  2. Define Non-Contact Force
  3. Difference Between Contact and Non-Contact Forces
Contact and Non Contact Force - Definition, Examples, Types, Difference, FAQs
Contact and Non Contact Force

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)

Also read -

Types of Contact Force

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

  1. Frictional Force: Force that opposes relative motion between two surfaces in contact.
  2. Normal Force: A surface force perpendicular to an object in contact with that surface.
  3. Tension Force: If you pull a string, rope or cable tight, you send a force through it.
  4. Applied Force: The force applied by one person or object to another person or object.
  5. 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.

Related Topics

NEET Highest Scoring Chapters & Topics
This ebook serves as a valuable study guide for NEET exams, specifically designed to assist students in light of recent changes and the removal of certain topics from the NEET exam.
Download E-book

Commonly Asked Questions

Q: Can you give examples of contact forces in everyday life?
A:
Common examples of contact forces include friction (between shoes and floor), normal force (book resting on a table), tension (in a rope pulling an object), and applied force (pushing a shopping cart). These forces all involve direct physical contact between objects.
Q: How do contact forces relate to Newton's Third Law of Motion?
A:
Contact forces always occur in pairs, as described by Newton's Third Law: for every action, there is an equal and opposite reaction. When you push on a wall (action), the wall pushes back on you with equal force (reaction).
Q: What role do contact forces play in friction?
A:
Contact forces are essential for friction. The normal force (perpendicular to the surface) and the irregularities of the surfaces in contact contribute to the frictional force, which opposes motion between the surfaces.
Q: How does air resistance fit into the classification of forces?
A:
Air resistance is a contact force, despite the fact that air is not visible. It occurs due to the collision of air molecules with the surface of a moving object, creating a drag force that opposes the object's motion.
Q: Can a single object experience both contact and non-contact forces simultaneously?
A:
Yes, objects often experience both types of forces simultaneously. For example, a book on a table experiences the contact force of the table (normal force) and the non-contact force of Earth's gravity simultaneously.

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).

Commonly Asked Questions

Q: How do non-contact forces affect the motion of planets?
A:
Non-contact forces, primarily gravity, govern the motion of planets. The gravitational attraction between a planet and its star keeps the planet in orbit, while the same force between planets influences their trajectories, all without direct physical contact.
Q: What is the relationship between electric and magnetic forces?
A:
Electric and magnetic forces are two aspects of the electromagnetic force, a fundamental non-contact force. Moving electric charges create magnetic fields, and changing magnetic fields induce electric fields, demonstrating their interconnected nature.
Q: How do non-contact forces influence atomic structure?
A:
Non-contact forces, specifically the electromagnetic force and nuclear forces, are crucial in atomic structure. The electromagnetic force holds electrons in orbitals around the nucleus, while nuclear forces bind protons and neutrons within the nucleus.
Q: Can non-contact forces cause deformation in objects?
A:
Yes, non-contact forces can cause deformation. For instance, tidal forces (a gravitational effect) can deform planets and moons, creating tidal bulges without direct physical contact between the bodies.
Q: What is the role of non-contact forces in particle physics?
A:
Non-contact forces, particularly the strong and weak nuclear forces, play a crucial role in particle physics. They govern the interactions between subatomic particles, holding quarks together to form protons and neutrons, and facilitating certain types of radioactive decay.

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.

Commonly Asked Questions

Q: What is the fundamental difference between contact and non-contact forces?
A:
Contact forces require physical touch between objects to exert influence, while non-contact forces can act at a distance without direct physical contact. This distinction is crucial in understanding how different forces operate in nature.
Q: What are some examples of non-contact forces?
A:
Non-contact forces include gravitational force (Earth's pull on objects), electromagnetic force (attraction or repulsion between charged particles), and nuclear forces (strong and weak forces within atomic nuclei). These forces can act across empty space without physical contact.
Q: How does gravity work as a non-contact force?
A:
Gravity is a fundamental force that attracts objects with mass towards each other. It acts at a distance through gravitational fields, allowing planets to orbit stars and objects to fall towards Earth without direct contact.
Q: Why is friction considered a contact force?
A:
Friction is a contact force because it only occurs when two surfaces are in direct physical contact and moving (or trying to move) relative to each other. The interaction between the microscopic irregularities of the surfaces creates the frictional force.
Q: Can non-contact forces be shielded or blocked?
A:
Some non-contact forces can be shielded or reduced, but not completely blocked. For example, electromagnetic forces can be shielded by certain materials, but gravitational forces cannot be shielded or blocked by any known means.

Frequently Asked Questions (FAQs)

Q: What is the relationship between non-contact forces and the concept of field in physics?
A:
Non-contact forces are often described using the concept of fields in physics. Gravitational, electric, and magnetic fields represent the influence of non-contact forces in space, allowing us to calculate the force on objects at any point within the field.
Q: How do contact forces contribute to the phenomenon of static electricity?
A:
Contact forces play a role in static electricity through the triboelectric effect. When certain materials are brought into contact and then separated, electrons can be transferred from one material to another due to the contact forces, resulting in static charge buildup.
Q: Can non-contact forces ever lead to the creation of new particles?
A:
Yes, non-contact forces can lead to particle creation. In high-energy physics, the strong nuclear force can create particle-antiparticle pairs from energy, as described by Einstein's famous equation E=mc².
Q: How do contact forces affect the propagation of sound waves?
A:
Sound waves propagate through media via contact forces between particles. As particles vibrate, they exert forces on neighboring particles, creating compressions and rarefactions that transmit the sound energy through the medium.
Q: What is the significance of non-contact forces in the study of plasma physics?
A:
Non-contact electromagnetic forces dominate the behavior of plasmas. The motion of charged particles in plasmas is governed by long-range electromagnetic interactions, leading to complex collective behaviors and phenomena like magnetic confinement.
Q: What role do contact forces play in the concept of impulse?
A:
Contact forces are crucial in understanding impulse, which is the product of force and time of application. In collisions, the contact forces between objects create an impulse that changes their momentum.
Q: How do non-contact forces affect the behavior of fluids?
A:
Non-contact forces, particularly gravity, significantly influence fluid behavior. Gravity causes pressure gradients in fluids, leading to phenomena like buoyancy and convection currents.
Q: Can non-contact forces ever create the appearance of contact forces?
A:
In some cases, non-contact forces can create effects that appear similar to contact forces. For example, magnetic levitation uses non-contact magnetic forces to support an object, mimicking the effect of a contact force like the normal force.
Q: How do contact forces relate to the concept of stress in materials?
A:
Contact forces are directly related to stress in materials. When external contact forces are applied to an object, they create internal forces (stress) that can lead to deformation or failure of the material.
Q: What is the significance of non-contact forces in quantum mechanics?
A:
Non-contact forces, particularly electromagnetic and nuclear forces, are fundamental in quantum mechanics. They govern the behavior of particles at the quantum level, influencing phenomena like electron orbitals and nuclear decay.
Articles