Motion (Physics)

                Motion(गति )

Understanding Motion and Inertia

This document provides a concise overview of motion and inertia, fundamental concepts in physics. It defines motion and rest, explores the concept of inertia as the resistance to changes in motion, and categorizes inertia into three types: inertia of rest, inertia of motion, and inertia of direction. It also touches upon the description of motion in terms of displacement, velocity, acceleration, and time.

Motion

Motion is defined as the change in the position of an object with respect to time. Conversely, an object is considered to be at rest when its position does not change with time.

In simpler terms:

• Motion: Object's position changes over time.

• Rest: Object's position remains constant over time.

Inertia

Inertia is the inherent property of an object that resists any change in its state of motion (or rest) along a straight line. It is a measure of an object's resistance to acceleration. The greater the mass of an object, the greater its inertia.

Types of Inertia

There are three primary types of inertia, each relating to a specific type of resistance to change:

1. Inertia of Rest: This is the tendency of an object to resist any change in its state of rest. An object at rest will remain at rest unless acted upon by an external force.

*   **Example:** A book lying on a table will remain there unless someone picks it up or something else moves it.

2. Inertia of Motion: This is the tendency of an object to resist any change in its state of motion. An object in motion will continue to move at a constant velocity (both speed and direction) unless acted upon by an external force.

*   **Example:** A hockey puck sliding on ice will continue to slide at a nearly constant speed and direction until friction slows it down or it hits something.

3. Inertia of Direction: This is the tendency of an object to resist any change in the direction of its motion. An object moving in a particular direction will continue to move in that direction unless acted upon by an external force that causes it to change direction.

*   **Example:** When a car makes a sharp turn, passengers tend to lean to the side because their bodies are resisting the change in direction.

Describing Motion

Motion can be described using several key parameters:

• Displacement: The change in position of an object. It is a vector quantity, meaning it has both magnitude and direction.

• Velocity: The rate of change of displacement with respect to time. It is also a vector quantity.

• Acceleration: The rate of change of velocity with respect to time. It is also a vector quantity.

• Time: The duration of the motion.

These parameters are interconnected and used to mathematically represent and analyze the motion of objects. For example, linear motion, which is movement along a straight line, can be described using equations that relate displacement, velocity, acceleration, and time.

गति एक भौतिकीय संगणना का मूल तत्व है जो किसी वस्तु के स्थान के परिवर्तन को संदर्भित करता है। यह स्थिति की परिवर्तन की दिशा, वेग, त्वरण और समय के संबंधों को व्यक्त करता है। गति की प्रकृति समय के साथ बदल सकती है और इसकी अवधारणा कई रूपों में हो सकती है, जैसे रैखिक गति, घुमावदार गति, और आवृत्ति गति। भौतिकी में, गति को विस्तार से अध्ययन किया जाता है और यह विभिन्न कारणों के परिणाम स्वरूप होती है, जैसे बाहरी बल, कक्षा, और संरेखण के विकास के फलस्वरूप। गति की अध्ययन मनुष्यों और यांत्रिकी में महत्वपूर्ण नियमों का पता लगाने में मदद करता है।

rotational motion (movement around an axis), and oscillatory motion (repetitive back-and-forth movement). The study of motion is a fundamental aspect of physics and is crucial in understanding the behavior of objects and systems in the physical world.

Scalar Quantities -Physical quantities which have magnitude only and no direction are called scalar quantities.

Example -Mass, Speed, Volume, work, time, power, energy etc.

अदिश राशियाँ - वे भौतिक राशियाँ जिनमें केवल परिमाण होता है और कोई दिशा नहीं होती, अदिश राशियाँ कहलाती हैं।

उदाहरण-द्रव्यमान, गति, आयतन, कार्य, समय, शक्ति, ऊर्जा आदि।

Vector Quantities -Physical quantities which have magnitude and direction both and obey triangle law are called vector Quantities.

Example -Displacement, velocity, acceleration, force, momentum, torque etc.

सदिश राशियाँ - वे भौतिक राशियाँ जिनमें परिमाण और दिशा दोनों होती हैं और त्रिभुज के नियम का पालन करती हैं, सदिश राशियाँ कहलाती हैं।

उदाहरण-विस्थापन, वेग, त्वरण, बल, संवेग, बल आघूर्ण आदि।

Distance -distance is the length of actual path covered by a moving object in a given time interval.

दूरी - दूरी एक निश्चित समय अंतराल में किसी गतिशील वस्तु द्वारा तय किए गए वास्तविक पथ की लंबाई है।

Displacement -Shortest distance covered by a body in a definite direction is called displacement.

विस्थापन - किसी पिंड द्वारा एक निश्चित दिशा में तय की गई सबसे कम दूरी को विस्थापन कहा जाता है।

Sir Isaac Newton 

The "laws of motion" refer to three fundamental principles formulated by Sir Isaac Newton in his work "Philosophiæ Naturalis Principia Mathematica" (Mathematical Principles of Natural Philosophy), commonly known as the Principia, published in 1687. These laws laid the groundwork for classical mechanics and remain foundational principles in the study of physics. They are:

1. Newton's First Law (Law of Inertia): This law states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force. In other words, objects tend to maintain their state of motion (either at rest or moving with constant velocity) unless an external force is applied to change that motion.

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3. Newton's Second Law (Law of Acceleration): This law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. Mathematically, it can be expressed as $�=��$, where $�$ is the net force applied to the object, $�$ is the mass of the object, and $�$ is the acceleration produced. This law explains how the motion of an object changes when subjected to external forces.

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5. Newton's Third Law (Action-Reaction Law): This law states that for every action, there is an equal and opposite reaction. In other words, whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object. These forces always occur in pairs and act on different objects.

1. न्यूटन का प्रथम गति का नियम (निष्क्रियता का नियम):- यह नियम कहता है कि किसी वस्तु को एक ही स्थान में रहने या सीधी रेखा में नियमित गति में रहने के लिए किसी बाह्य बल की आवश्यकता होती है। अर्थात, किसी वस्तु को अपनी स्थिति को बदलने के लिए कोई परिस्थिति की आवश्यकता होती है।

   उदाहरण: एक कठिन पथ पर लगातार चलती ट्रेन, जो एक बार आराम कर दिया जाए, उसे वहां ही रुकने की प्रवृत्ति होती है।

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3. न्यूटन का दूसरा गति का नियम (त्वरण का नियम):- यह नियम कहता है कि किसी वस्तु की त्वरण उस पर लगाए गए बाह्य बल के अनुपात में होती है और उसकी मास के अनुपात में उल्टा होती है।

   उदाहरण: एक गाड़ी को ठीक तरह से ब्रेक लगाने पर वह धीरे-धीरे रुकती है, यह एक उदाहरण है कि त्वरण कैसे किसी वस्तु की गति को बदलता है।

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5. न्यूटन का तीसरा गति का नियम (क्रिया-प्रतिक्रिया का नियम): -यह नियम कहता है कि प्रत्येक क्रिया के लिए एक समान और विपरीत प्रतिक्रिया होती है।

   उदाहरण: -जब एक व्यक्ति पत्थर को पठार पर मारता है, तो वह पत्थर को मारता है, लेकिन समय के साथ, पत्थर भी व्यक्ति को पीछे की ओर धकेलता है। यह दोनों ही क्रिया और प्रतिक्रिया का उदाहरण है।

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Together, these laws provide a framework for understanding the relationships between the motion of objects and the forces acting upon them. They are fundamental principles in classical mechanics and have broad applicability across various fields of physics and engineering.