Class 11 Physics - KERALA
Laws of Motion
The chapter Laws of Motion in Class 11 Physics builds upon the concept of force and kinematics to explain why objects move the way they do. Based on the Kerala SCERT syllabus, you will study Newton's three laws of motion, momentum, the law of conservation of linear momentum, and the mechanics of friction including static, kinetic, and rolling friction. Additionally, you will learn about uniform circular motion and solving connected body problems using free-body diagrams. This chapter is fundamentally important for higher secondary board exams, carrying a significant weightage of around 6 to 8 marks, and forms the core of classical mechanics for competitive exams like NEET and JEE.
Start Learning FreeKey Concepts
Newton's First Law of Motion
An object continues to remain at rest or in uniform motion along a straight line unless acted upon by an external force; this property is known as inertia.
Newton's Second Law of Motion
The rate of change of momentum of an object is directly proportional to the applied external force and takes place in the direction in which the force acts (F = dp/dt).
Newton's Third Law of Motion
To every action, there is always an equal and opposite reaction acting on two different bodies.
Conservation of Linear Momentum
The total linear momentum of an isolated system of interacting bodies remains conserved if no external force acts on the system.
Friction
The opposing force that arises when one body moves or tends to move over the surface of another, categorized mainly into static, limiting, and kinetic friction.
Centripetal Force
The necessary force directed towards the center of a circular path required to keep an object moving in a uniform circular motion.
Important Formulas
Board Exam Info
In the Kerala SCERT Class 11 Physics board examination, the Laws of Motion chapter typically carries around 6 to 8 marks. Expect numerical problems based on Newton's second law, conservation of momentum, and friction, along with direct derivation questions such as banking of roads and recoil of a gun.
Frequently Asked Questions
Why do action and reaction forces not cancel each other out?
Action and reaction forces do not cancel each other because they act on two different bodies, not on the same body.
What is the difference between static and kinetic friction?
Static friction acts on objects when they are at rest relative to the surface, while kinetic friction acts when the object is actually sliding over the surface. Static friction is always greater than kinetic friction.
Why are roads banked on curved paths?
Banking of roads provides the necessary centripetal force required for safe vehicle turning without relying solely on frictional force, reducing wear and tear on tires.
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