What is Force?

If you see people walking or running across a pavement or a narrow street, have you ever wondered what allows them to do such? Or have you asked yourself what makes you move from a place to another? The answer all boils down to a scientific concept which we unknowingly take advantage of every single day of our lives. In order for you to move, force must be applied.

Simply put, force is a physical concept that causes an object to move in a particular direction. It could be applied in almost everywhere and everything: from cars and rockets to animals and human beings. It could take several forms in order to get work done. These would include physical activities such as pushing and lifting, to atomic and subatomic particles.


But there is more to force than the reason for our movement. On this article, we are going to delve into the basics surrounding force. Additionally, we are going to describe and different balanced force and unbalanced force.

Force, according to laws of Physics, refers to the interaction which causes an affected objected to either be pushed or pulled into a particular direction. This results in a change to the state of the momentum of an object. So whenever there is an interaction that happens between two objects, there is a force that is acted upon on each of the objects. The force could either be a push or a pull depending on the interaction. If the interaction fails to continue, the objects will no longer experience any force.

Additionally, such force causes things to accelerate, change in direction, add to the overall pressure of an object or even change in shape. The aforementioned acceleration would refer to the movement of a free object with a finite mass relative to a steady frame of reference. One of the most common examples of this would be the thrust that causes a car or any vehicle to speed up when the accelerator has been stepped on.

A force is a vector quantity. It is noted as such because a force is a quantity that has both direction and magnitude. Hence, in order to completely describe the force that is acting upon an object, there must be the magnitude (which is numerical), and the direction. Moreover, force is commonly represented using diagrams wherein a force is symbolized by an arrow. The size of the arrow would depend upon the magnitude of the force. The direction of the arrow, on the other hand, denotes the direction where the force is acting. In addition to this, because force is a vector, the effect of a singular force on an object is frequently canceled by the effect of another force which is acted upon on the object.

It is worth noting that force should be defined in mechanical terms. However, it could result from various actions such as magnetic fields, particle bombardment, and electric fields, among others. It should also be noted that force has the property to impart acceleration to objects or particle.

Unit of Measurement

The strength of a force is expressed in ‘Newton‘. A Newton could be abbreviated by an, “N”. A Newton, which could be expressed as 1 N or 1 Newton, refers to the amount of force that is required in order to give an object that is 1 kilogram an acceleration of 1 m/s/s. It could also be expressed in dyne. A dyne is equal to one gram per centimeter per second square.

Force could be determined using the Second Law of Motion by Isaac Newton. The formula is as follows: F=m.a where ‘F’ refers to the force, ‘m’ stands for the mass of the object, and ‘a’ refers to the acceleration of the object. Newton’s formula indicates that an object will move faster when a force is acted upon on such object. If the object is heavy but the force is weak, it would take a long period of time for its speed to be increased.

To measure force, there are various tools which could be used. One of the tools is the force meter. This gear contains a spring that is connected to a metal hook. The spring stretches whenever a force has been applied to the hook. It should be noted that the bigger the force which has been applied, the longer the spring would stretch, the bigger the reading of force.

Types of Forces

Force could be classified into different forms. The first one is the external force. It refers to the force that acts on an object due to the interaction with the environment that surrounds it. It could either be contact or non-contact. The second type of force is the internal force which refers to the force that acts within the body. An example would be the force that has been exerted on the bones, tendons, muscles, and ligaments, among others.

Force could also be categorized as:

  1. Contact Forces
  2. Non-contact Forces (Action-at-a-distance force)

Contact force refers to the force that is produced when two interacting objects are seen to be contacting each other physically. This would include frictional forces, air resistance forces, and tensional forces, among others.

Non-contact Forces, on the other hand, refers to the force that is produced when two interacting objects are not in contact with each other yet they are able to exert a push and pull kind of force. A common example of such kind of force is gravitational pull. Others would include electrical force and magnetic force.

Balanced and Unbalanced Forces

Force could also be classified as balanced and unbalanced.

When talking about balanced force, we are referring to the force that is opposite indirection but equal in size. This would be considered as the force in a state of equilibrium. Hence, when there is a balanced force, their no change in direction. They are always equal to zero. Additionally, such force could not change the direction or the motion of an object.

An actual example of balanced force include the force that is exerted by an object, say a book for instance, that is counteracted by the normal force or support force of a table. The two forces are completely opposite and equal to each other.

Unbalanced force, on the other, refers to the forces that are not opposite in terms of direction and size. Hence, there is always a cause which changes in motion. When two unbalanced forces are exerted in different and opposite directions, the combined force would be the difference between the two forces.

For example, two people who push a box sitting on the floor on opposite sides, the person with less weight would exert less force than the person on the right side of the box.

To summarize their differences, we need to identify several bases for comparison. In terms of magnitude, balanced forces are equal while unbalanced forces are not equal. In terms of the force exerted by stationery objects, balanced forces would allow these objects to stay at rest while unbalanced forces would allow them to move in the direction of the greater force. In terms of moving objects, such objects subjected to balanced forces would continue to move in the same speed while objects subjected with unbalanced forces would change its speed and direction. Finally, in terms of net force, balanced forces have zero while unbalanced forces have non-zero.

Reference: Toppr
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