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NEWTON LAW OF MOTION in 110 Minutes || Full Chapter Revision || Class 11th JEE

JEE Wallah・2 minutes read

Newton's Laws of Motion outline the relationship between forces, acceleration, and momentum, emphasizing the importance of external forces for acceleration. Equilibrium questions involve balancing forces, applying principles like Hooke's law and gravitational force for accurate calculations and problem-solving in physics.

Insights

Newton's Laws of Motion explain how external forces affect acceleration and momentum in physics, emphasizing the balance between action and reaction forces.
Equilibrium scenarios focus on balancing forces in all directions, with forces like tension, gravitational force, and normal force playing crucial roles.
Understanding the application of pseudo forces in non-inertial frames is essential for accurate force calculations in accelerated scenarios.
Analyzing relative motion and acceleration in scenarios involving multiple bodies requires equalizing acceleration components towards a common normal to ensure equilibrium.

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Recent questions

What is Newton's third law of motion?
For every action, there is an equal and opposite reaction.
What is the law of inertia?
A body at rest remains at rest.
How is acceleration calculated in Newton's second law?
Acceleration equals force divided by mass.
What is the significance of distinguishing action and reaction forces?
Action and reaction forces form pairs.
How are equilibrium questions approached in physics?
Equilibrium involves balancing forces in all directions.

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Summary

00:00

Newton's Laws: Force, Acceleration, Momentum Explained

Newton's Law of Motion explains that for every action, there is an equal and opposite reaction.
The law involves two regions of velocity change, either in magnitude or direction, leading to acceleration.
The first law of motion, known as the law of inertia, states that a body at rest remains at rest, and a body in motion continues at a constant velocity unless acted upon by an external force.
Newton's second law relates the rate of change of momentum to the net external force acting on a body or system, with momentum being mass times velocity.
The second law mathematically expresses force as the product of mass and acceleration, emphasizing external forces causing acceleration.
The third law asserts that every action has an equal and opposite reaction, with forces acting in the same nature but opposite directions on different bodies.
The law of motion highlights the importance of external forces in providing acceleration, as internal forces do not contribute to acceleration.
Understanding the third law involves recognizing that the reaction force is equal in magnitude, opposite in direction, and simultaneous to the action force.
Distinguishing between action and reaction forces can be challenging, as one action leads to a corresponding reaction, forming a pair of forces.
The comprehensive understanding of Newton's Laws of Motion is crucial for grasping the principles of force, acceleration, and momentum in physics.

11:24

Forces in Physics: Action and Reaction

If force is exerted on object A by object B, object B will also exert a force back on object A.
Newton's third law states that for every action, there is an equal and opposite reaction.
The concept of force is integral in physics, including external forces like net force, which equals mass multiplied by acceleration.
Various types of forces are studied in physics, such as normal force, gravitational force, tension force, and spring force.
Gravitational force is the force exerted by one mass on another, like the Earth pulling objects towards its center.
Tension force arises when a rope is pulled, with the rope always pulling away from the body.
Normal force is the force exerted by a surface on an object in contact with it, like the ground pushing back on an object placed on it.
When multiple objects are in contact, forces are exerted between them, such as normal forces between two objects touching each other.
In equilibrium, the net force on an object is zero, with forces balancing each other out, as seen in mathematical equations.
Ideal springs are those with negligible mass and uniform stiffness, crucial in physics problems where they are considered ideal for simplicity.

22:22

Understanding Equilibrium and Spring Forces

Natural length of a spring refers to its relaxed state when left undisturbed.
Natural length is determined by measuring the spring when it is not pulled or compressed.
Hooke's law in elasticity states that spring force is directly proportional to the distance it is pulled or compressed.
Spring force is calculated as F = k * x, where x is the distance from the natural length.
Ideal pulleys in Newton's law of motion have zero mass and no friction, resulting in equal tension on both sides.
In equilibrium, the net force in all directions is zero, ensuring balance between forces.
Equilibrium questions involve balancing forces in x and y directions.
Equilibrium scenarios can be solved by breaking forces into components and ensuring balance.
Equilibrium questions often involve determining unknown masses based on balanced forces.
Equilibrium questions can be approached by setting up Free Body Diagrams and analyzing forces.

35:21

Equilibrium and Tension in Balanced Forces

2t = 50, t = 25
Mass is involved in the scenario
Equilibrium is discussed
Forces are balanced: up equals down, right equals left
Front force minus rear force equals mass times acceleration
Acceleration is calculated as forward force minus rear force divided by total mass
Shortcut method: Net external force equals total mass times acceleration
Tension is calculated using the shortcut method
Acceleration is determined by pulling force minus compressive force divided by total mass
Modified version of the second law: F net external equals m1 a1 + m2 a2 + m3 a3 + m4 a4, where common acceleration is derived from a1, a2, a3, a4
Tension is calculated using the shortcut method with multiple masses
Tension is determined by considering the entire system and calculating the forces above and below
Tension can be measured using a spring balance system or a reading machine to find the normal reaction

47:06

Physics Concepts: Spring Cutting and Pseudo Forces

Inclined motion of an inclined plane involves acceleration, calculated as force minus stopping force divided by total mass.
Practice questions quickly to revise concepts and prepare for similar questions in exams.
Questions may involve scenarios like lifting masses or monkeys, determining minimum forces or accelerations.
Spring cutting involves dividing a spring into pieces, with the product of spring constant and length remaining constant.
Cutting springs affects forces and accelerations, requiring understanding of spring properties and forces.
Questions may involve determining accelerations and forces after spring cuts, maintaining equilibrium conditions.
Understanding spring cutting concepts is crucial for solving related questions accurately.
Pseudo forces, like tension and wedge constraints, are important concepts to understand in physics.
Pseudo forces, such as those in elevators with acceleration, require clear understanding and application in problem-solving.
Practice and understanding of various physics concepts, including spring cutting and pseudo forces, are essential for exam preparation.

58:51

Understanding Pseudo Forces in Accelerated Frames

When a person raises their hand holding a mobile phone, the acceleration experienced by the phone is the same as that of the hand.
The equation for this scenario involves the mass of the object multiplied by the acceleration, resulting in the normal reaction force.
An observer inside a lift experiences a normal reaction force, which is determined by the mass and acceleration.
The concept of normal reaction force is further explored when an individual sits inside a lift and calculates the forces at play.
The presence of a normal reaction force is crucial in understanding the equilibrium of forces in different frames of reference.
Newton's laws fail to apply in non-inertial frames, such as those experiencing acceleration.
To rectify this, pseudo forces are introduced to account for the effects of acceleration in non-inertial frames.
Pseudo forces are calculated based on the mass of an object and the acceleration experienced in the non-inertial frame.
Applying pseudo forces is essential when analyzing scenarios involving accelerated frames, ensuring accurate force calculations.
By incorporating pseudo forces, calculations involving accelerated frames can be accurately solved, leading to a better understanding of forces at play.

01:10:44

Equilibrium and Pseudo Force Calculations Simplified

Infection settling leads to peace; block causing pause and equilibrium.
Equilibrium questions involve equal top and bottom forces.
Pseudo force calculation: m*a, crucial for correct answers.
Equilibrium questions require careful calculations and understanding.
Pseudo force not always necessary, especially when on the ground.
Acceleration and equilibrium calculations simplified by sitting inside a moving vehicle.
Calculations involving blocks and masses for equilibrium and acceleration.
Importance of understanding pseudo force and gravitational force interactions.
Effective concept: altering gravitational force with acceleration for easier calculations.
Zooming in and out metaphorically represents entering a new world of calculations.

01:23:01

Forces, Tension, and Motion in Elevators

Initial question posed about a block with a weight of 10 kg, discussing forces and tension.
Upward force equating downward force, resulting in an answer of 100.
Block placed inside a lift with acceleration upwards, answer being a = 2.
Concept of g effective introduced, calculated as m * g, leading to g + 2.
Mass calculated as 10 times 12, resulting in 120.
Introduction of pseudo force and gravitational force in the lift scenario.
Question regarding finding the time for an object to fall down.
Application of equations of motion to determine time.
Discussion on relative motion in a lift scenario.
Explanation of the concept of g effective and its application in calculations.

01:35:30

"Acceleration, Force, Mass: Solving Physics Equations"

The acceleration is below g, which is 10.
The force is moving downwards.
The mass is 4m.
The force below is bigger.
The force below is equal to 4m * a2.
The third equation comes from Kansan motion.
The equation is t * a1 + 2t * a2 = 0.
The acceleration will be downwards.
The acceleration will be upward.
The acceleration of each block is found by solving three unknowns.

01:47:09

Balancing Acceleration Components for Relative Motion

To determine relative motion and acceleration, focus on finding the components of acceleration for both bodies moving towards a common normal. Ensure that the accelerations of both bodies are equalized by eliminating the common normal component.
Acceleration calculations involve identifying a1 and a2, with a1 being the acceleration of the green body and a2 being the acceleration of the pink body. These accelerations must be equalized by considering their components towards the common normal direction.
The process involves equalizing the components of acceleration for both bodies, ensuring there is no relative motion towards the common normal. By following this method, the acceleration components can be balanced, leading to a clear understanding of the scenario.

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