MPPSC Mains PYQs

Newton’s Laws of Motion: The Mantra of Classical Mechanics

Sir Isaac Newton, one of the greatest scientists in history, established the foundation of classical mechanics when he introduced his three laws of motion. These laws, which he articulated in great detail in the seminal book “Philosophiæ Naturalis Principia Mathematica” in 1687, provide a comprehensive system for understanding what makes things move. So now—let’s dive into each law and what that means.

The First Law of Motion (Newton’s First Law): The Law of Inertia

So far, well behind you, you could not hear the third statement: A body at rest tends to stay at rest, and a body in motion tends to stay in motion with the same speed and in the same direction unless acted on by an unbalanced force.

Explanation:

Third Law: The Third Law deals with the concept of inertia, or an object keeps its state of motion (rest or motion). Inertia is directly proportional to an object’s mass; the more mass that exists, the more inertia there is, and thus the harder it is to push that object.

Or, more simply put: An object stays at rest, or in motion at constant speed in a straight line, unless acted on by a net external force. Meaning a stationary object will remain stationary, and a object in motion will remain in motion in the same direction and at the same speed unless acted upon by an outside force.

Unbalanced Force: An unbalanced force is a force that is not balanced with an equal and opposite force. It means that, for example, a ball moving along a surface without friction, will never stop, until some external force (friction, impact, etc) occurs.

For example, imagine a book on a table. So based on Newton’s first law, the book will stay where it is (at rest) until a force, such as a push or a pull, is applied to it. Similarly, a state 1 car on a straight and flat road is completely torque-free; it will continue to move at constant velocity until something external, say the brakes or a speed bump, puts it in some other state.

Second of Newton Laws of Motion: The Law of Acceleration

Best paraphrase:Law: An object acted upon by a net force will accelerate in the direction of the net force. a). The acceleration of an object is directly proportional to the magnitude of the net force acting on the object and inversely proportional to the mass of the object. b).

To define Bolds ( F = ma )

Force(F): The net force that acts on an object is the vector sum of the forces that act on the object.

It is a measure of an object’s reluctance to change its state of motion.

Acceleration (a): It represents how much the velocity of an object is changing with respect to the time.

Explanation:

Directly Proportional: The acceleration of an object is directly proportional to the net force applied to it, and inversely proportional to the mass of the object.

Not Only Proportional also Inversely as well: Given a constant net force, doubling the mass will halve the acceleration.

Knowing the net force tells the direction of the acceleration vector on the basis of Newton’s second law.

For instance, consider a shopping cart. So if you have a cart and you give it a little push. It can go faster than that, if you push it harder. On the other hand, if the cart’s mass doubles (say you throw a whole slew of stuff into it), it will require twice the amount of force to achieve the same amount of acceleration.

The Third Law of Motion : The Law of Action and Reaction

This is to say that for every action there is an equal and opposite reaction.

Explanation:

It is one of the laws of motion. Thus these forces are on two different objects and have the same magnitude and are oppositely directed.

Format: Axle weighing; Date with a clear start; External (velocities and lengths) and internal (forces, moments, and principles) angles; Force pairs always; To each action, anti-action. They don’t cancel each other out — they act on different objects.

Example: If you jump, your legs will push against the ground (action). Then the ground pushes back an equal and opposite reaction onto your body, and pushes you up into the air. Similar is when a rocket expels gas from its engine (action). As the gas recoils backward, it exerts an equal and opposite force on the rocket (the second half of newtons symbols), propelling the rocket backwards.

Implications and Applications

Principle of Inertia: Compared to seat-belts of safety measures, the principle of inertia is important to understand. When a vehicle comes to an abrupt halt, one that is inside continues to move forward due to inertia. A seatbelt resists this motion to protect the occupant.

Motion Dynamics: Newton’s 2nd law is the groundwork in engineering and physics to find the forces required to reach the desired accelerations. It is used in engineering for vehicle trajectories and modeling the behavior of mechanical systems; it is used in the academic study of projectiles; and it’s used in the planning of spacecraft and trajectories.

Momentum Conservation: Newton’s third law lays the groundwork for momentum conservation. In a closed system, the momentum before and after an interaction is conserved. This postulate is the basis for collisions, explosions, and interactions of particles in all physical environments.

Conclusion

In physics, Newton’s laws of motion is the basis of classical mechanics and describe it with simplicity, but can still have complex applications to moving bodies. These laws have been tried, tested and proven time and again through the centuries and are fundamental in our understanding of the physical world. So in short, The Newton’s laws of motion is the shell of classical mechanics which gives the basic idea of how the forces act on the objects and how the objects move under the influence of various forces which provides a rough initial understanding of its wide variety of applications like from the everyday experience to the advanced engineering to high energy physics.