Are you aware of the Force? Know more.
Force is a very familiar word that we encounter daily. But it is more than that what we understood. Then what is force? When you push or pull an object, it may or may not displace. What you apply yourself to display the object towards a direction is referred to as a force.
What is force?
When you push or pull an object, it may or may not displace. What you apply yourself to display the object towards a direction is referred to as a force. Thus force is an external agency, required to set an object in motion, in a particular direction. In short, force is a vector quantity, which possesses both magnitude and direction. Force is a physical quantity that is equal to the product of the mass of the body and its acceleration.
Formula of force; F=m.a, F=force, m=mass of an object, a=acceleration. The Force formula is defined by Newton’s second law of motion.
You have to use SI units for measurement; Newton or Dyne for force, Kilogram for mass, and meter per second squared for acceleration.
Types of forces:
Forces are two types -contact forces and noncontact forces.
The force that needs contact with the objects, is known as contact force. In other words, the force can not act without physical contact with the objects or bodies. Contact force has different types, such as normal force, frictional force, applied force, tension force, air resistance force, and spring force.
The force applied to an object by an object or by a body or a person is called applied force. Examples:
- Push or pull a table.
- Kick a football.
- Pushing a door to open.
Formula; F=m.a, F=force, m=mass of an object, a=acceleration
The normal force is everyday force. When a surface pushes against an object, placed on the surface, the act is the normal force. Let us take an example, when a book is kept on a table, the normal force keeps the book on the table, acting against the gravitational force. Here both force act perpendicular to the surface in the opposite direction in the same magnitude. Newton’s third law of motion is applied to the normal force. Examples:
- The book is placed on the table.
- Water bottle kept on the desk.
- Books kept on self.
- A block on a ramp.
Formula-N=mgcosθ, F=normal force, m=mass of the body, g=gravitational force, θ=angle of the inclined surface.
The force generated by the friction of two surfaces or contacts sliding against each other is known as friction force. Further, we may say the force which opposes the motion of one object or body over the other in contact is the frictional force. Examples:
- Driving a vehicle on the road.
- Walking or running on the road.
- Pressing iron against a shirt.
- Drilling a nail into a wall.
- Drawing/ pushing an object on the surface.
Formula-F=μmg, F=friction force, mg=normal force, μ=coefficient of friction.
A force transmitting through a rope, string, cable or chain, or wear, or any material, when pulled by forces acting from the other side, is called tension force. Tension force is opposite to compressed force and similar to elastic potential energy. Examples:
- Pulling a bucket of water from a well.
- Crane machine.
- Tug of war.
Formula- T=mg+ma, T=tension (N or Kg-m/s2 g=acceleration due to gravity (9.8 m/s2)
Air resistance force:
Air resistance is a force caused by air when an object moves through it. This force act against the movement of an object or acts in the opposite direction of the object passing through it. Examples:
- When an aircraft flies through the air, air flows/ air particles resist the movement of the aircraft from opposite directions.
- A rocket is launched being resisted by air particles.
- Parachute in air
Formula: FD=1/2 Pv2CDA, FD=drag (in fluid dynamics, it is called drag), P=density of fluid, v=speed of the object relative to the fluid, CD= drag coefficient, A= cross-section area.
Spring is a well-known object, that can be deformed by using a force and it gets back its original form if the force is removed called spring force. We may also say a force, which is required to compress or stretch the spring upon any object attached to it is known as a spring force. The spring force was discovered by British physicist Robert Hooke (1660), for which it is also referred to as Hooke’s law force. Examples:
- Watches and toys.
- Pogo stick.
Formula: F=k(x-x0 ), F= spring force, x0= equilibrium position, x= the distance of the spring from its position at equilibrium, k=spring constant.
The force is exerted/applied without physical contact between two objects or bodies. Noncontact force is further classified into three categories; gravitational force, electrical force, and magnetic force.
According to Newton’s universal law of gravitation, it is a force that pulls two masses towards each other. In other words, every object having mass draws other objects with mass towards its center of gravity due to gravitational force.
Objects with more mass have more gravitational forces than objects of lesser mass. The magnitude of the gravitational force depends on the distance between the two objects and with the increase of the distance between the objects gravitational force decreases. It is a universal law. Examples-
- All stars, satellites, galaxies, and black holes are bound by the law of gravity or gravitational forces.
- Our own solar system.
- Every object touches the ground if displaced from its position.
Sir Isaac Newton formulated the gravitational theory in the year 1665-1666, after watching an apple falling on the ground.
Formula: F=G m1m2/r2, F= force,m1=mass of object 1, m2= mass of object 2,r=distance between centre of the masses.
The repulsive or attractive interaction between two charged particles or objects is known as an electric force. Here one negative and one positive charge body /object attracts each other. It is an attractive force between electrons and the nucleus. Further negative, negative and positive bodies repulse each other.
It is also referred to as coulomb force /electrostatic force/ coulomb interaction/ attraction or repulsion of particles or objects. It is called the coulomb force, as a French physicist, Charles Augustin de Coulomb 1785 discovered the equation of electrical force. Examples:
- Charge in a bulb.
- Rubbing the rod with silk cloth.
- Television screen.
Formula: Ke=1/4ПƐ0, Ke= coulomb’s constant, П=pi, Ɛ0=electric constant
Magnetism is caused by the motion of electric charge particles. Every object /article is made up of very tiny particles called atoms and every atom has charged particles like nuclei and electrons.
Magnetic force is the result of the attraction or repulsion of electrically charged particles of objects due to their motion. It is due to the effect exerted upon either charge by a magnetic field created by the other. Two negative charges repulse each other like two positive charges and a negative charge attracts a positive charge. Examples;
- Magnet pulls coins.
- A compass.
- Train tracks.
Formula-F=qvBsinθ, F=magnetic force, q=charge of moving particles, v= velocity of the particle, B=magnetic field, θ=angle between velocity and magnetic field vectors.
In everyday life, we encounter different forms of forces every moment. But as ordinary people, we are not aware of it. Force is the binding external agency that holds the entire universe intact. My above discussion is just an outline of the much bigger chapter like force.