StudyTunnel Logo
StudyTunnel
by BhamuIntelli Systems LLP

Home

School

CBSE

Class 11 Science (PCM)

Physics Part 1

Laws of Motion

Laws of Motion

Action PlanNotesQuestionsMock-Test
Study Action Plan (Sorted by Difficulty)
Solving Mechanics Problems Using Newton’s Laws
Accuracy: 36%
Total Attempted22
Total Correct8
Total Incorrect14
Difficulty Level:
High
Conservation of Momentum
Accuracy: 49%
Total Attempted47
Total Correct23
Total Incorrect24
Difficulty Level:
High
Frictional Forces
Accuracy: 52%
Total Attempted27
Total Correct14
Total Incorrect13
Difficulty Level:
Medium
Common Forces and Free Body Diagrams
Accuracy: 54%
Total Attempted71
Total Correct38
Total Incorrect33
Difficulty Level:
Medium
Normal Reaction, Tension and Spring Force
Accuracy: 55%
Total Attempted38
Total Correct21
Total Incorrect17
Difficulty Level:
Medium
Equilibrium of Forces
Accuracy: 57%
Total Attempted23
Total Correct13
Total Incorrect10
Difficulty Level:
Medium
Friction on Inclined Planes and Connected Bodies
Accuracy: 63%
Total Attempted19
Total Correct12
Total Incorrect7
Difficulty Level:
Medium
Impulse and Momentum
Accuracy: 65%
Total Attempted34
Total Correct22
Total Incorrect12
Difficulty Level:
Medium
Newton's Second Law of Motion
Accuracy: 67%
Total Attempted61
Total Correct41
Total Incorrect20
Difficulty Level:
Medium
Newton's First Law of Motion
Accuracy: 68%
Total Attempted19
Total Correct13
Total Incorrect6
Difficulty Level:
Medium
Circular Motion and Centripetal Force
Accuracy: 69%
Total Attempted32
Total Correct22
Total Incorrect10
Difficulty Level:
Medium
Newton's Third Law of Motion
Accuracy: 85%
Total Attempted20
Total Correct17
Total Incorrect3
Difficulty Level:
Low

Learning Objectives

Top

Learning Objectives

  • Understand the concept of inertia and its relation to Newton's First Law of Motion.
  • Calculate the force required to change the state of motion of a body using Newton's Second Law of Motion, expressed as F=maF = ma.
  • Analyze interactions between bodies using Newton's Third Law of Motion, which states that forces occur in equal and opposite pairs.
  • Apply the principle of Conservation of Momentum to isolated systems to solve collision and explosion problems.
  • Differentiate between static, kinetic, and rolling friction, and calculate the forces involved in various scenarios.
  • Derive the expression for centripetal force required for circular motion and solve problems involving circular dynamics.
  • Use the concept of impulse to determine the change in momentum resulting from short-duration forces.
  • Solve equilibrium problems by ensuring the vector sum of all forces acting on a particle is zero.
  • Construct and interpret free-body diagrams to identify forces such as weight, normal reaction, tension, spring force, and friction in mechanics problems.
  • Apply friction laws to inclined planes and connected body systems to calculate tension and acceleration.
  • Solve complex mechanics problems using Newton’s Laws by systematically resolving forces, choosing appropriate axes, and writing equations for multi-body systems.

Practice, Analyze & Improve

Dont just read—test your knowledge! Unlock the Student Workspace to take chapter tests and get instant performance insights.

Deep Analytics

Peer Comparison

Track Progress

Claim Free Account100% Free • No credit card required

Revision Notes & Summary

Top

Chapter Notes

Newton's First Law of Motion

  • Definition: A body remains in its state of rest or uniform motion unless acted upon by an external force.
  • Concept of Inertia: Inertia is the resistance of any physical object to any change in its velocity. This includes changes to the object's speed or direction of motion.
  • Implications: If no net external force acts on an object, it will maintain its current state of motion.

Newton's Second Law of Motion

  • Formula: F=maF = ma
    • F: Net external force acting on the body
    • m: Mass of the body
    • a: Acceleration of the body
  • Rate of Change of Momentum: The rate of change of momentum of a body is proportional to the net external force acting on it.
  • Vector Nature: The second law is a vector equation, meaning it applies to each component of the vectors involved.
  • Local Law: The force at a point at a certain instant determines the acceleration at that point at that instant.

Newton's Third Law of Motion

  • Statement: For every action, there is an equal and opposite reaction.
  • Force Pairs: Forces always occur in pairs, and these pairs act on different bodies.

Conservation of Momentum

  • Isolated System: In an isolated system, the total momentum remains constant if no external forces act on it.
  • Collision Example: In a collision, the total momentum before impact is equal to the total momentum after impact.

Frictional Forces

  • Types of Friction:
    • Static Friction: Opposes the initiation of motion.
    • Kinetic Friction: Opposes the relative motion between surfaces in contact.
    • Rolling Friction: Much smaller than static or kinetic friction, occurs when a body rolls over a surface.
  • Coefficient of Friction: Denoted by μ\mu, it is a measure of how much frictional force exists between two surfaces.

Circular Motion and Centripetal Force

  • Centripetal Force Formula: F=mv2RF = \frac{mv^2}{R}
    • m: Mass of the body
    • v: Velocity of the body
    • R: Radius of the circular path
  • Application: For a car on a circular track, friction provides the necessary centripetal force.

Impulse and Momentum

  • Impulse: Product of force and the time duration over which it acts, resulting in a change in momentum.
  • Formula: Impulse=F×Δt=Δp\text{Impulse} = F \times \Delta t = \Delta p

Equilibrium of Forces

  • Condition: A particle is in equilibrium when the vector sum of all forces acting on it is zero.
  • Concurrent Forces: Forces that act on a particle at the same point.

Common Forces and Free Body Diagrams

  • Identification of Forces: Weight, normal reaction, tension, spring force, friction, contact force, buoyant force.
  • Free Body Diagrams: Useful for visualizing forces acting on a single body.

Normal Reaction, Tension and Spring Force

  • Normal Reaction: Perpendicular contact force.
  • Tension: Force in a string or rope.
  • Spring Force: Given by Hooke's Law, F=−kxF = -kx.

Friction on Inclined Planes and Connected Bodies

  • Inclined Planes: Friction opposes motion down the plane.
  • Connected Bodies: Analyze using free body diagrams and Newton's laws.

Solving Mechanics Problems Using Newton’s Laws

  • Steps:
    • Draw free-body diagrams.
    • Resolve forces into components.
    • Apply Newton's laws to each body.
    • Solve the resulting equations for unknowns.
Do you belong in the Top 10%?

Our analytics show that most students struggle with specific concepts in Laws of Motion. Take a free diagnostic test to generate your personal Learning DNA profile.

Practice Test – MCQs, True/False

Top

Multiple Choice Questions

A.

The object moves in the direction of the force.

B.

An equal and opposite force is exerted by the object.

C.

The object remains stationary.

D.

The object accelerates indefinitely.
Correct Answer: B

Solution:

Newton's Third Law states that for every action, there is an equal and opposite reaction. Therefore, when a force is applied to an object, an equal and opposite force is exerted by the object.

Chapter Concept:

Newton's Third Law of Motion

A.

Impulse is the product of force and distance.

B.

Impulse is the product of force and time, resulting in a change in momentum.

C.

Impulse is the rate of change of velocity.

D.

Impulse is the force required to keep a body in motion.
Correct Answer: B

Solution:

Impulse is defined as the product of force and time, which results in a change in momentum. It is particularly significant in short-duration force applications.

Chapter Concept:

Impulse and Momentum

A.

a=Fma = Fm

B.

a=Fma = \frac{F}{m}

C.

a=mFa = \frac{m}{F}

D.

a=F×ma = F \times m
Correct Answer: B

Solution:

Newton's second law states that the acceleration aa of a body is given by a=Fma = \frac{F}{m}, where FF is the net force applied and mm is the mass of the body.

Chapter Concept:

Newton's Second Law of Motion

A.

Rolling friction is greater than static friction.

B.

Rolling friction is independent of the weight of the object.

C.

Rolling friction is much smaller than static or sliding friction.

D.

Rolling friction does not occur in the absence of air resistance.
Correct Answer: C

Solution:

Rolling friction is much smaller than static or sliding friction, often by 2 or 3 orders of magnitude.

Chapter Concept:

Common Forces and Free Body Diagrams

A.

F=−kxF = -kx

B.

F=kxF = kx

C.

F=kxF = \frac{k}{x}

D.

F=kx2F = kx^2
Correct Answer: A

Solution:

The force exerted by a spring is given by Hooke's Law, F=−kxF = -kx, where kk is the spring constant and xx is the displacement from the equilibrium position.

Chapter Concept:

Normal Reaction, Tension and Spring Force

A.

vmax=Rgtan⁡Θv_{\text{max}} = \sqrt{Rg \tan \Theta}

B.

vmax=Rgv_{\text{max}} = \sqrt{Rg}

C.

vmax=μsRgv_{\text{max}} = \sqrt{\mu_s Rg}

D.

vmax=Rgtan⁡Θv_{\text{max}} = \sqrt{\frac{Rg}{\tan \Theta}}
Correct Answer: A

Solution:

For a banked road with no friction, the maximum permissible speed is given by vmax=Rgtan⁡Θv_{\text{max}} = \sqrt{Rg \tan \Theta}.

Chapter Concept:

Frictional Forces

A.

1000 N

B.

2000 N

C.

500 N

D.

None of the above
Correct Answer: A

Solution:

The centripetal force required is given by f=mv2R=1000×10250=1000 Nf = \frac{mv^2}{R} = \frac{1000 \times 10^2}{50} = 1000 \text{ N}. Thus, the frictional force required is 1000 N.

Chapter Concept:

Newton's Third Law of Motion

A.

0.2 m/s20.2 \text{ m/s}^2 upward

B.

0.2 m/s20.2 \text{ m/s}^2 downward

C.

9.8 m/s29.8 \text{ m/s}^2 upward

D.

0 m/s20 \text{ m/s}^2
Correct Answer: A

Solution:

The net force on the block is T−mg=100−98=2 NT - mg = 100 - 98 = 2 \text{ N}. Using F=maF = ma, the acceleration a=210=0.2 m/s2a = \frac{2}{10} = 0.2 \text{ m/s}^2 upward.

Chapter Concept:

Normal Reaction, Tension and Spring Force

A.

2 m/s²

B.

3 m/s²

C.

4 m/s²

D.

5 m/s²
Correct Answer: A

Solution:

The frictional force fkf_k is given by fk=μkN=0.2×5×9.8=9.8f_k = \mu_k N = 0.2 \times 5 \times 9.8 = 9.8 N. The net force FnetF_{net} acting on the object is F−fk=20−9.8=10.2F - f_k = 20 - 9.8 = 10.2 N. Using Newton's second law, Fnet=maF_{net} = ma, we find a=10.25=2.04≈2a = \frac{10.2}{5} = 2.04 \approx 2 m/s².

Chapter Concept:

Impulse and Momentum

A.

Action and reaction forces act on the same body.

B.

Action and reaction forces are equal in magnitude and opposite in direction.

C.

Action precedes reaction in time.

D.

Action and reaction forces cancel each other on the same body.
Correct Answer: B

Solution:

Newton's third law states that for every action, there is an equal and opposite reaction. These forces act on different bodies.

Chapter Concept:

Conservation of Momentum

Experience the StudyTunnel Method

We do not just give you mock tests. We guide you through a gamified, AI-driven learning path designed to guarantee mastery.

Step 1: Practicing the Concepts

Laws of Motion

Step 2: Master Boss Exam
Locked • Full Phase Assessment
Step 3: Redemption Arena
Locked • AI Weakness Tracker

True or False

Correct Answer: False

Solution:

For a car on a horizontal road, the centripetal force is provided by the frictional force between the tires and the road, not by the gravitational force.

Chapter Concept :

Circular Motion and Centripetal Force

Correct Answer: False

Solution:

Newton's second law states that the acceleration of a body is directly proportional to the net external force acting on it and inversely proportional to its mass. Therefore, the acceleration is dependent on the net external force.

Chapter Concept :

Newton's Second Law of Motion

Correct Answer: True

Solution:

The second law of motion applies to both a single point particle and a system of particles, as long as the force considered is the total external force on the system, and the acceleration is that of the system's center of mass.

Chapter Concept :

Newton's Second Law of Motion

Correct Answer: True

Solution:

In an isolated system, the total momentum remains constant if no external forces act on it, as stated in the law of conservation of momentum.

Chapter Concept :

Conservation of Momentum

Correct Answer: True

Solution:

The spring force is described by Hooke's Law, which states that the force exerted by a spring is proportional to the displacement from its equilibrium position and is directed opposite to the displacement.

Chapter Concept :

Normal Reaction, Tension and Spring Force

Correct Answer: True

Solution:

On a banked road, the horizontal component of the normal force contributes to the centripetal force, allowing for a higher maximum speed compared to a flat road where only friction provides the centripetal force.

Chapter Concept :

Friction on Inclined Planes and Connected Bodies

Correct Answer: False

Solution:

The normal reaction force is equal to the gravitational force only when the body is at rest on a horizontal surface without any additional forces acting on it. In other situations, such as on an inclined plane or when additional forces are applied, the normal force may differ from the gravitational force.

Chapter Concept :

Normal Reaction, Tension and Spring Force

Correct Answer: False

Solution:

The total momentum of an isolated system is conserved in both elastic and inelastic collisions, as long as no external forces act on the system.

Chapter Concept :

Conservation of Momentum

Correct Answer: True

Solution:

The normal reaction force is defined as the component of contact force that acts perpendicular to the surface of contact.

Chapter Concept :

Common Forces and Free Body Diagrams

Correct Answer: True

Solution:

Centripetal force is defined as the force required to keep a body moving in a circular path, and it is always directed towards the center of the circle.

Chapter Concept :

Circular Motion and Centripetal Force

AI Learning Assistant
Top

I can help you understand Laws of Motion better. Ask me anything!

Summarize the main points of Laws of Motion.
What are the most important terms to remember here?
Explain this concept like I'm five.
Give me a quick 3-question practice quiz.
StudyTunnel Methodology

We dont just provide random mock tests. Our AI-driven, phase-wise learning system is designed to guarantee mastery from your first chapter to your final exam.

1
Master the Concepts

Start with chapter notes, formulas, and common exam mistakes. Practice with thousands of MCQs, True/False, and Descriptive questions with instant solutions.

2
Conquer Boss Exams

Once you master individual chapters, unlock Phase-wise Boss Exams. These milestone tests simulate the actual exam environment to test your retention across multiple subjects.

3
The Redemption Arena

The ultimate learning hack. Our AI tracks every mistake you make and dynamically generates custom tests targeting your weak points until you achieve 100% accuracy.