Class 11 Physics - BIHAR
Laws of Motion
The chapter Laws of Motion in Class 11 Physics builds the foundation of classical mechanics, exploring why objects move the way they do. Students study Newton's three laws of motion, the concept of inertia, linear momentum, and the principle of conservation of momentum. It also covers important practical forces like friction, tension, and circular motion dynamics including centripetal force. For Bihar School Examination Board (BSEB) students, this is a high-scoring and crucial chapter. It frequently features numerical problems on connected bodies, inclined planes, and conceptual derivations that are essential for both theory exams and competitive tests like JEE and NEET.
Start Learning FreeKey Concepts
Newton's First Law of Motion
An object continues to remain at rest or in uniform motion unless an external force acts on it, defining the property of inertia.
Newton's Second Law of Motion
The rate of change of linear momentum of a body is directly proportional to the applied external force and takes place in the direction of the force, given by F = ma.
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 objects remains conserved if no external force acts on it.
Friction
An opposing force that arises when two surfaces are in contact, categorized into static, limiting, and kinetic friction.
Important Formulas
Board Exam Info
In the Bihar (BSEB) Class 11 Physics examination, the Laws of Motion chapter along with Work, Energy and Power carries around 8 to 12 marks. Common question types include short-answer conceptual questions on inertia and friction, numerical problems based on Newton's second law and connected bodies (like blocks on pulleys or inclined planes), and derivations of the conservation of momentum.
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 friction and kinetic friction?
Static friction acts when objects are at rest relative to each other and adjusts its value, whereas kinetic friction acts when objects are in relative motion and is almost constant.
Why is it easier to pull a lawn mower than to push it?
When pulling, the vertical component of the pulling force acts upwards, reducing the normal reaction and hence the friction. When pushing, it increases the normal reaction and friction.
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