Is Gravity An External Force:Exhaustive Insights


There is the external and internal force that could be studied depending on the type of work. Let us see in detail about is gravity an external force.

It is possible to have various forms of forces that will never affect the overall mechanical energy of an item but will instead just transfer the energy of an object from potential to kinetic energy (or vice versa). Internal forces and external forces are the two types of forces that may be found in a given circumstance.

In this article, we will study is gravity an external force or an internal force by comprehending the ideas of internal and external forces.

Is gravity an external force?

Gravity is not an external force.

The gravitational force or gravity between two particles in a system is defined as when two particles in a system are attracted to one another. When we investigate gravitational force, we are looking at the interaction of two or more particles. Moreover, the gravitational pull conserves the overall amount of energy. As a result, gravity is considered an internal force.

External Force Vs. Internal Force

Many classification systems are used to classify the various kinds of forces.

It was stated that all forces might be classified as contact or action-at-a-distance. A force’s classification as an action-at-a-distance force depends on whether it may exist even when objects are not physically touching. Even if two items aren’t physically touching, they can still be affected by forces like gravity, electricity, and magnetism.

It is possible that some types of forces, when present and when involved in the performance of work on things, will cause the total mechanical energy of the item to be altered. A force that can never have an effect on an item’s total mechanical energy, but can only transfer the energy of an object from its potential to its kinetic state, is referred to as a kinetic energy. 

Internal forces and external forces are the two types of forces that may be found in a given situation. So, that means internal and external forces based on whether or not their existence has the capability of altering the overall mechanical energy of an object.

There are numerous excellent approaches to explain and distinguish internal and external forces. However, for the purposes of this discussion, we will logically conclude that external forces are comprised of the applied force, the normal force, the tension force, the friction force, and the air resistance force. However, internal forces comprise gravity, magnetic, electrical, and spring forces for our needs.

Non-conservative and Conservative forces

In order to understand the significance of classifying a force as either internal or external, it is necessary to understand how that type of force may modify the total mechanical energy of an item when it performs work on that object.

Non-Conservative Force:

A change in the total mechanical energy (KE + PE) of an item occurs when net work is performed on it by an external force. It is possible for an item to gain energy if the work is positive. It is possible for an item to lose energy if the work is negative. The increase or decrease in energy might take the form of potential energy, kinetic energy, or a combination of the two. In such conditions, the amount of work completed will be equal to the amount of mechanical energy that has been changed in the item.

“Nonconservative forces” refer to external forces that have the ability to modify the total mechanical energy of an object due to the fact that they have the power of affecting the total mechanical energy of an object.

Conservative Force:

It is possible for an object’s total mechanical energy (KE + PE) to remain constant even if the object’s principal source of net work is internal force (for example, gravitational and spring forces). When this occurs, the object’s energy takes on a different form. In the case of an object “forced” to drop from a high height to a low elevation due to gravity, part of the potential energy of the object is converted into kinetic energy as a result of gravity.

Conversely, the total amount of kinetic and potential energy remains constant during the experiment. Energy conservation is the term used to describe this.

However, when internal forces are the sole ones conducting the work, energy can alter forms, going from kinetic to potential (or vice versa), but the overall value of mechanical energy is conserved. It is for this reason that internal forces are sometimes referred to as conservative forces because they are capable of modifying the form of energy without increasing the total quantity of mechanical energy contained inside a system.

The above explanation is simply the detailed answer on is gravity an external force.

Internal force examples

Internal forces – gravitational and spring forces – are the only ones that perform work on the items described in the following examples. This results in the transformation of energy from KE to PE (and vice versa), while the overall quantity of mechanical energy is preserved. How the energy is transferred between KE and PE should be the subject of each description.

1. If in the absence of air resistance, a ball falls from a height of 2 meters.

→ A decrease in height (dropping) and an increase in velocity are being experienced by the ball. In order to do this, the internal or conservative force (gravity) is used to convert energy from Potential Energy (height) to Kinetic Energy (velocity).

2. When a dart is launched from its original resting position, the spring of a dart gun exerts a force on the dart.

→ After undergoing a transition from a compressed to a relaxed condition, the spring is forced forward, propelling the dart onward. This transition causes the internal or conservative force (spring) to transfer energy from Potential Energy (a compressed spring) to Kinetic Energy (speed).


Frequently Asked Questions (FAQs):

Q. What do you mean by an external force?

Ans: Any body can feel force externally or internally.

An external force is defined as the force applied to an item from the outside. It can be either a contact or a non-contact force. An external force is mostly a contact force, which occurs when an item interacts with its environment. 

Read more on the external force examples in detail.

Q. What are different types of an external force?

Ans: There are five types of an external force

Read more on the types of external force

Q. What do you mean by internal force?

Ans: On the basis of their interaction with the system, forces are classified as internal or external forces, respectively.

When a force operates on a system internally, it is referred to as an internal force. This force either causes a change in the system or opposes a change in the system caused by an external force. In a system, internal forces are generated within the system, and they are unable to cause an external change in the system, such as an acceleration of the system or a change in the system’s kinetic energy.

Read more on examples of the internal force.

Q. What are the different types of internal force?

Ans: There are four types of an internal force.

  • Bending
  • Compression
  • Tension
  • Torsion

Prajakta Gharat

I am Prajakta Gharat. I have completed Post Graduation in physics in 2020. Currently I am working as a Subject Matter Expert in Physics for Lambdageeks. I try to explain Physics subject easily understandable in simple way.

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