# Resistant Body: Definition, and Examples

By Deepak Yadav|Updated : October 31st, 2022

Before we go into the specifics of the resistant body, let's first understand the body. Body refers to anything that has mass and occupies some volume. For example, an atom is also a body, a box, and a car is also a body. A resistant body is a body that is not rigid yet behaves like one while operating in a machine.

Resistant Body PDF

In practice, nobody is rigid since motion or force is always transmitted through some deformation. As a result, the body should resist transmitting motion or force. Although resistant bodies are undeformable for their purpose, they may get distorted when employed in other high-load conditions. Let's dive deep into the concepts related to the resistant body.

## Resistant Body

A resistant body is a body that is not rigid yet behaves like one while operating in a machine. In practice, nobody is rigid since motion or force is always transmitted through some kind of deformation. As a result, the body should resist transmitting motion or force. GATE exam may carry MCQ-based question on resistant body or concepts related to it.

### Example of Resistant Body

A machine is a collection of rigid or resistant bodies that are made and connected in such a way that they move in specific relative motions and transmit force from the source of power to the resistance to be overcome. Examples of a resistant body are as follows:

• A chair that can support 120kg will behave like a rigid body up to that weight, but if the load is increased, it may deform. As a result, this chair is known as a resistant body.
• The cycle chain is the resistant body because it functions like a rigid body while transmitting motion to the cycle's rear wheel. The belt is in a belt and pulley setup.

## What is Rigid Body?

A rigid body is a solid body with no or minimal deformation that may be ignored. The distance between any two points on a rigid body remains constant over time, regardless of the external forces or moments acting on it. A rigid body is typically thought of as a continuous distribution of mass. Rigid bodies and its concepts are conceptually important for GATE question paper.

A totally rigid body does not exist in the study of special relativity, and objects can only be assumed to be rigid if they are not travelling near the speed of light. Equilibrium of rigid body is one of the essential topics of the GATE notes. A rigid body is commonly thought of in quantum mechanics as a collection of point masses. Molecules, for example, are frequently seen as hard bodies.

## Difference Between Resistant Body and Rigid Body

Rigid bodies do not deform (regardless of the quantity and nature of force/torque applied). They do not exist in the real world; they are merely ideas.

Resistant bodies, on the other hand, are undeformable for the purpose they serve, but they may get deformed when used in other high-stress scenarios.

## Linear and Angular Position

A rigid body's position is the position of all the particles that make it up. To simplify the description of this posture, we take advantage of the body's rigidity, which means that all of its particles keep the same distance relative to each other. If the body is stiff, describing the position of at least three non-collinear particles is sufficient. This allows you to reconstruct the position of all the other particles if you know their time-invariant position relative to the three selected particles. However, a different, mathematically more convenient, but identical strategy is frequently adopted. The entire body's position is indicated by:

• The linear position or location of the body, specifically the position of one of the body's particles chosen as a reference point (typically coinciding with the centre of mass or centroid of the body).
• The body's angular position (also known as orientation or attitude).
 Important GATE Notes Work Done By A Force Motion Under Gravity Dynamic Resistance Static Resistance Ideal Diode Bettis Theorem Work Done By A Constant Force Application Layer Protocols Castiglia's Theorem Portal Frames

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• Although resistant bodies are undeformable for the purpose they serve, they may become distorted when used in other high-load scenarios.

• A rigid body is a solid body idealized in which deformation is ignored. In other words, regardless of the external forces acting on a rigid body, the distance between any two given places remains constant over time. A metal rod is an example of a stiff body.

• A rigid body is a perfect body that does not deform or change shape. Formally, it is described as a collection of particles with the feature that the distance between particles remains constant as the body moves. Three types of rigid bodies are static, dynamic, and kinematic.

•  Regardless of the force applied, no part of a rigid body moves relative to another section of the body. A rigid body is equivalent to a system of particles with fixed spacing between them.

• A non-rigid body is a branch of a tree that bends easily and directly when bent. Our electrical wires are frequently twisted. It is not an example of a rigid body. Hence it is a nonrigid body.

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