##### Aakash iACST Scholarship Test 2024

ApplyGet up to 90% scholarship on NEET, JEE & Foundation courses

Edited By Vishal kumar | Updated on Aug 28, 2023 11:59 AM IST

**NCERT Solutions for Class 11 Physics Chapter 6 Work Energy and Power** play a crucial role in the mechanics section of the 11th grade. Moreover, this chapter of NCERT Solution serves as the cornerstone for several subsequent chapters. To achieve high scores in your Class 11 exams or competitive tests like JEE and NEET, it's essential to grasp work energy and power Class 11 numericals with solutions thoroughly and efficiently tackle its questions.

**JEE Main Scholarship Test Kit (Class 11): Narayana | Physics Wallah | **

**NEET Scholarship Test Kit (Class 11): ****Narayana** **| Physics Wallah** **| ****Aakash**** | ****ALLEN**

**Suggested: ****JEE Main: high scoring chapters | ****Past 10 year's papers**

**New:** **Aakash iACST Scholarship Test. Up to 90% Scholarship. Register Now**

This Story also Contains

- NCERT Solutions for Class 11 Physics Chapter 6 – Download Free PDF
- NCERT Solutions for Class 11 Physics Chapter 6 Work, Energy and Power
- NCERT Solutions for Class 11 Physics Chapter 6 Work Energy and Power - Exercise Questions
- NCERT Solutions for Class 11 Physics Chapter 6 Work Energy and Power Additional Exercise
- NCERT solutions for class 11 physics chapter wise
- Tips to score good marks in class 11 Physics Chapter 6 NCERT solutions
- Some of The Main Points on Work Energy and Power Class 11 Topic-Collisions
- Importance of NCERT Solutions for Class 11 Physics Chapter 6 Work Energy and Power
- Subject wise NCERT Exemplar solutions
- Subject wise NCERT solutions

On this page of Careers360, you will find comprehensive class 11 physics chapter 6 exercise solutions from Question 6.1 to 6.30. along with, additional exercise questions designed by subject experts. These solutions are presented in a clear, step-by-step manner that is easy to understand.

Consider that you are carrying a 10 Kg stationary in your hand and you are not moving. In this situation, you are doing work physically according to you. But according to physics, you are doing zero work. Can you find out why work is zero here? Work Energy and Power ch 6 Physics class 11 has questions based on the concepts of work and types of work, the relation between work and energy and the concept of power. In the CBSE NCERT solutions for Class 11 Physics Chapter 6 Work Energy and Power, you will study problems on the law of conservation of energy (energy can be neither created nor destroyed).

NCERT solutions for Class 11 Physics Chapter 6 Work Energy and Power also give answers to the questions based on the concepts of collision, which are important for the exam. Solutions of NCERT are helpful in scoring well in class and board exams. Solutions for both exercise and additional exercise in the NCERT are given. Students can also download Work Energy and Power Class 11 NCERT solutions pdf by clicking on the link download PDF for free.

**NCERT Class 11 Physics Chapter 6 Exercise Solutions**** pdf download**** **for free.

****According to the CBSE Syllabus for the academic year 2023-24, the chapter you previously referred to as Chapter 6, "Work, Energy and Power" has been renumbered as Chapter 5.**

work done by a man in lifting a bucket out of a well by means of a rope tied to the bucket.

** Answer:**

In this case, the direction of force and displacement are the same, this work done is ** positive**.

** Answer: **

In this case, the direction of displacement is upward and the direction of force is downward. Thus work done is** negative **in nature.

** Answer: **

We know that friction acts in the direction opposite to the direction of motion. Hence work done by the frictional force is **negative**.

** Answer: **

In this case, the applied force supports the motion of the object (balances frictional force). Thus work done by the force is **positive**.

** Answer: **

Work done in this case is **negative ** as the direction of force and motion are not identical.

** Answer: **

Using Newton's law we can write :

The frictional force is given by :

Its direction will be opposite of the direction of the motion. Thus acceleration produced will be negative.

Thus the net acceleration is = 3.5 - 0.98 = 2.52 m/s ^{ 2 } .

The total distance travelled is given by :

or

Hence the work done by applied force is given by :

** Answer: **

The work done by frictional force will be negative as the force opposes the motion.

** Answer: **

The net work done will be the sum of work done by applied force and work done by frictional force.

** Answer: **

It is given that initial velocity is zero. The final velocity can be calculated by the equation of motion :

or

or

Thus change is kinetic energy is :

or

or

** Answer: **

Total energy = kinetic energy (KE) + potential energy(PE)

** KE > 0 since m and v ^{ 2 } is positive. If KE <0 particles cannot be find. If PE>TE, then KE<0 (now in all graph check for this condition) **

** In case 1 ** kinetic energy is negative for x<a. So at x<a particle cannot be found.

** In case 2 ** for x<a and for x> b kinetic energy is negative. So the particle cannot be found in these regions.

** In the third case ** , the minimum potential energy is when . At this position, the potential energy is negative (- V _{ 1 } ).

The kinetic energy in this case is given by :

And the minimum energy of particle is - V _{ 1 } .

** In the fourth case ** , the particle will not exist in the states which will have potential energy greater than the total energy.

Thus particle will not exist in and .

The minimum energy of particle will be - V _{ 1 } as it is the minimum potential energy.

** Answer: **

The total energy of the particle is given by :

or

At the extreme position, the velocity of the object is zero thus its kinetic energy at that point is zero.

or

or

or

Hence the extreme position are .

** Answer: **

The total energy is given by :

or

The burning of casing results in a reduction in the mass of the rocket. This leads to a lowering in the total energy.

Thus heat required for burning is obtained from the expenses of the ** rocket ** .

** Answer: **

This is because the gravitational force is a conservative force. And we know that the work done by a conservative force in a closed path is always zero. That's why the work done by the gravitational force is zero in a complete orbit revolution.

** Answer: **

The total energy of artificial satellite remains constant. Thus when it approaches towards the earth the distance between them decreases. This results in a decrease in the potential energy of the satellite. By energy conservation, the kinetic energy of satellite increases and so does the velocity.

** Answer: **

In the first case,

Work done is :

or

or

or

In the second case :

or

or

Thus work done in the second case is greater than the first case.

** Answer: **

It is given that work done by the conservative force is positive, thus the force acts in the direction of the motion. This results in a decrease in distance between the bodies. Thus it's potential energy ** decreases ** .

** Q6 (b) ** Work done by a body against friction always results in a loss of its kinetic/potential energy.

** Answer: **

Work done by the body against friction results in a decrease in the velocity of the body. Thus the kinetic energy of the body decreases.

** Answer: **

The internal force cannot produce a change in the total momentum as no external force is acting. Thus the change in total momentum is proportional to the external forces acting on the body.

** Answer: **

The conservation of ** total linear momentum ** doesn't depend upon the fact whether it is an elastic collision or an inelastic collision.

** Q7(a) ** State if each of the following statements is true or false. Give reasons for your answer.

In an elastic collision of two bodies, the momentum and energy of each body is conserved.

** Answer: **

** False: ** - The linear momentum and energy will be conserved if both are considered in a system. But for individual bodies, this conservation of momentum and energy doesn't hold. This is because the impact during the collision may transfer energy/momentum of one ball to the other ball.

** Answer: **

** False: ** - Internal forces will not change the energy of the system but external forces can change the total energy by changing their magnitude or direction.

** Answer: **

** False:- ** This is true only for conservative forces e.g. gravitational force. For e.g in case of frictional force (non-conservative force), the work done in a closed-loop cannot be zero as energy is wasted throughout.

** Answer: **

** True but not always:- ** In the case of inelastic collisions, few amounts of energy is converted into other forms of energy such as sound or in deformation. Thus final kinetic energy is always less as compared to initial kinetic energy. But in case of the explosion of a bomb final kinetic energy is greater than the initial kinetic energy

** Answer: **

No, because at the time of the collision, the kinetic energy is converted to the potential energy. Thus total kinetic energy is not constant at the collision.

** Q8 (b) ** Is the total linear momentum conserved during the short time of an elastic collision of two balls?

** Answer: **

Yes, in case of elastic collision the total linear momentum of the system remains conserved as no external force is acting on the system of balls.

** Q8 (c) ** What are the answers to (a) and (b) for an inelastic collision?

** Answer: **

The total kinetic energy of the system cannot be conserved in case of inelastic collision as there is loss of energy in the form of deformation. But the total linear momentum of the system remains constant even in the case of inelastic collision as no external force is acting.

** Answer: **

Since the potential energy of the system depends upon the separation between the bodies thus the forces acting on the body are conservative in nature. We know that conservative forces produce elastic collisions.

** Answer: **

It is given that acceleration is constant thus force will also be constant (by Newton's law of motion F = ma).

Also,

or

Thus

Now, the work done by the force is given by :

Hence power is directly proportional to the time.

** Answer: **

We know that the power is given by :

or

or

It is given that power is constant, thus :

or

By integrating both sides, we get

Also, we can write :

or

By integrating we get the relation :

** Answer: **

Force is given to be :

And the displacement is :

Thus the work done is given by :

or

or

** Answer: **

The kinetic energy of the electron is given by :

or

Thus velocity is obtained as :

or

Similarly, we can find the velocity of the proton :

Thus velocity is obtained as :

or

Thus the ratio of their velocities is :

** Answer: **

The volume of the drop is :

Thus the mass of raindrop is :

or

Thus the work done is given by :

or

or

or

Now the total energy at the peak point is :

or

or

And the energy at the ground is :

or

or

Thus work done by the resistive force is :

** Answer: **

The momentum is conserved in the collision as no external force is acting on the system. In the given case the rebound velocity is the same as the initial velocity thus the kinetic energy of the molecule initially and finally are same. Hence this is an elastic collision.

** Answer: **

Mass of the water is :

or

Thus the output power is given by :

or

or

or

Also, we are given that efficiency is 30 per cent.

Thus the input power is :

or

** Answer: **

The initial kinetic energy of the system is given by :

or

** Case (i):- ** The final kinetic energy is :

Thus the kinetic energy is not conserved in this case.

** Case (ii):- ** The final kinetic energy is :

** Thus kinetic energy is conserved in this case. **

** Case (iii):- ** The final kinetic energy is:-

or

Thus the kinetic energy is not conserved in this case.

** Answer: **

This is an elastic collision thus the transfer of momentum will take place. It is given that bob B is at rest and bob A has some velocity. So in momentum transfer, bob B will gain the velocity in the left direction whereas bob A will come to rest (complete momentum transfer takes place).

Hence bob A will not rise.

** Answer: **

Consider the extreme position (horizintal) :-

The kinetic energy at this position is zero as velocity is zero.

Thus total energy is given by :

Now consider the mean position (lowermost point) :

Here the potential energy of bob is zero.

Whereas kinetic energy is :

Further, it is given that 5 per cent of energy is dissipated due to air resistance while coming down.

Thus energy equation becomes (conservation of energy):-

or

** Answer: **

Since the sand is falling in the trolley thus the force generated on the system (trolley and sandbag) is an internal force. There is no external force thus momentum of the system doesn't change. Hence speed remains the same i.e., 27 Km/hr.

** Answer: **

The relation between work done and the kinetic energy is given by :

Using the relation we can write :

Initial velocity = 0 (at x = 0 )

And the final velocity = (at x = 2).

Thus work done is :

or

or

** Answer: **

The volume of wind = here is the swept circle and is the velocity.

Thus the mass of the wind is : - _{} , is the density of the air.

Hence mass of wind flowing through windmill in time t is _{ . }

** Q21 (b) ** The blades of a windmill sweep out a circle of area A. What is the kinetic energy of the air?

** Answer: **

The kinetic energy is given by :

or

or

Thus the kinetic energy of wind is _{} J.

** Answer: **

It is given that 25 per cent of wind energy is converted into electrical energy.

Thus electric energy produced is :

or

Now the electric power is given by :

or

or

or

** Answer: **

The work done against the gravitational force is given by :

= Number of times the weight is lifted work done in 1 time.

or

or

** Answer: **

Efficiency is given to be 20 per cent.

Thus energy supplied by the person :

Thus the amount of fat lost is :

or

** Answer: **

It is given that the efficiency of energy conversion is 20 per cent.

According to question, we can write (equating power used by family) :

(Here A is the area required.)

or

or

Thus required area is 200 m ^{ 2 } .

** Q23 (b) ** A family uses 8 kW of power. Compare this area to that of the roof of a typical house.

** Answer: **

A typical has dimensions of .

The area of the roof of the house is .

This is nearly equal to the area required for the production of the given amount of electricity.

** Answer: **

We are given :

Mass of the bullet m: 0.012 Kg

Mass of the block M: 0.4 Kg

The initial velocity of the bullet u: 70 m/s

The initial velocity of the block : 0

The final velocity of the system (bullet + block): v

For finding the final speed of system we will apply the law of conservation of momentum :

or

Now for the system, we will apply the law of conservation of energy :

The potential energy at the highest point = Kinetic energy at the lowest point

or

or

or

Hence heat produced is :

or

or

** Answer: **

The FBD of the track is shown in the figure below :

Using the law of conservation of energy we have :

or

Hence both stones will reach the bottom with the same speed.

** For stone 1 ** we can write :

or

** For stone 2 ** we have :

Also, using the equation of motion,

or

It is given that

or

Thus

Hence, the stone travelling on the steep plane will reach before.

For finding speed and time we can use conservation of energy.

or

or

or

And the time is given by :

and

** Answer: **

Displacement (x) of the block is given as : = 0.1 m.

Using equilibrium conditions we can write :

and ( _{} is the frictional force).

We can write work done in terms of potential energy as :

or

or .

Thus the coefficient of friction is 0.125.

** Answer: **

In this case, the heat produced is the loss in the potential energy.

Thus,

heat produced = mg h

or

or

The heat produced (when the lift is stationary) will remain the same as the relative velocity of the bolt with respect lift still remains zero.

** Answer: **

The initial momentum of the system (boy + trolley) is given as :

Now assume * v * ' is the final velocity of the trolley with respect to the ground.

Then the final momentum will be :

Conserving momentum :

or

The time taken by the boy is :

Hence the distance moved by the trolley is :

** Answer: **

The potential energy of the system depends inversely on the separation between the balls. Thus the potential energy will decrease as the balls will come closer and will become zero as they touch each other.

Thus elastic collision is best described only by the graph (v).

[Note: The simple result of this exercise was one among the several arguments advanced by W.

Pauli to predict the existence of a third particle in the decay products of This

particle is known as the neutrino. We now know that it is a particle of intrinsic spin ½ (like

e—, p or n), but is neutral, and either massless or having an extremely small mass

(compared to the mass of an electron) and which interacts very weakly with matter. The

correct decay process of the neutron is : ]

** Answer: **

By Einstein’s mass-energy relation we can write :

Here and C are constant thus two-body decay is unable to explain (or account for) the continuous energy distribution in the * β * -decay of a neutron.

class 11 physics chapter 6 ncert solutions consist of a total of thirty questions. These questions cover topics such as basic work energy and Power, Enistein's mass-energy relation, friction in an inclined plane, total energy and more. Step-by-step solutions made by subject matter experts of Careers360 can provide students with a comprehensive understanding of these concepts and help them prepare for exams. By studying **NCERT Solutions for Class 11** Physics Chapter 6 PDF, students can improve their problem-solving skills and gain confidence in their ability to tackle physics problems.

JEE Main Highest Scoring Chapters & Topics

Just Study 40% Syllabus and Score upto 100%

Download EBookKnowing how important formulas and diagrams are in Class 11th Physics, Chapter 6 NCERT Solutions is key. These tools really help understand concepts and solve problems well. To help you learn better, here are the important formulas and diagrams for this chapter:

#### Work done

[SI unit = joule (J) and dimension = ML^{2}T^{2} ]

#### Kinetic energy

(KE) = 1/2mv^{2}=P^{2}/2m

#### Potential Energy

U_{G}=mgh

U_{SPRING} = 1/2kx^{2}

#### Work-Energy Theorem

W = Change in K. E. of a body =Δ KE

#### Power

P= w/t

To score good marks in Physics Class 11 Chapter 6, you can follow these steps using NCERT Solutions:

**Understand the Concepts:**Read the chapter work power energy class 11 thoroughly to understand the concepts and principles involved in it. Try to understand the definitions, laws, and equations used in the chapter.**NCERT solution:**Use chapter 6 physics class 11 ncert solutions provided on our careers360 website. These solutions provide detailed explanations and solutions to all the problems given in the textbook.**Practice Problems:**Practice the problems provided in the NCERT Solutions chapter-wise and try to solve them on your own. This will help you understand the concepts better and improve your problem-solving skills.**Revise Regularly:**Revise the concepts regularly to ensure that you have a strong foundation in the subject.**Solve Sample Papers and Previous Years' Question Papers:**Practice sample papers and previous years' question and NCERT Exemplar Class 11 Physics Solutions.

By following these steps, you can use the class 11th physics chapter 6 ncert solutions to score good marks in your exams.

- For an elastic collision, Law of conservation of momentum and that of Kinetic Energy holds good
- For inelastic collision Law of conservation of momentum hold good but kinetic energy is not conserved
- Coefficient of restitution is the ratio of relative velocity after the collision to relative velocity before the collision
- For a perfectly elastic collision coefficient of restitution is one
- For inelastic collision coefficient of restitution is less than one
- For a perfectly inelastic collision coefficient of restitution is zero

**Expert-Crafted Solutions:**The work energy and power class 11 numericals with solutions have been meticulously prepared by subject matter experts, ensuring a comprehensive understanding of each question. The use of simple language makes it easier for students to follow along.**Thorough Explanation:**All thirty questions in the exercise are explained in detail, breaking down each step to clarify the reasoning behind the solution approach. This helps students grasp not only the answer but also the underlying concepts.**Additional Exercise Questions:**In addition to the main exercise questions, there are extra practice questions included. These extra questions are designed to enhance problem-solving skills and reinforce the chapter's concepts.**Comprehensive Coverage:**The class 11th physics chapter 6 ncert solutions cover all aspects of the chapter, including key concepts, formulas, and diagrams. This ensures a well-rounded understanding of the topics discussed in Chapter 6.**Easy Accessibility:**Students can access these solutions conveniently, enabling them to study and revise the chapter effectively, ultimately leading to a stronger grasp of the subject matter.

- Many questions were answered in the solutions of NCERT Class 11 Physics chapter 6 Work Energy and Power based on the concept of the work-energy theorem which is important throughout the physics course. The concept will be used in class 12 also.
- NCERT solutions for class 11 will help to score well in-class exams and also competitive exams like NEET.
- Learning NCERT solutions will help to solve problems from other reference books also.

**NCERT Physics Exemplar Solutions Class 11 For All The Chapters:**

- NCERT Exemplar Class 11th Solutions
- NCERT Exemplar Class 11th Maths
- NCERT Exemplar Class 11th Physics
- NCERT Exemplar Class 11th Chemistry
- NCERT Exemplar Class 11th Biology

- NCERT Books Class 11 Physics
- NCERT Syllabus Class 11 Physics
- NCERT Books Class 11
- NCERT Syllabus Class 11

1. What is the weightage of Class 11 chapter Work Energy and Power for NEET exam

On an average 4% questions are asked for NEET from Work Energy and Power. To prepare for NEET exam NCERT book is the one of the preffered materials. Along with NCERT exercise questions students can also practice NCERT exemplar and NEET previous year papers.

2. How many questions comes from Work Energy and Power for JEE Main

One or two question can be expected from the chapter Work Energy and Power for JEE Main based on the previous year paper analysis. But the concepts studied in Work Energy and Power Class 11 chapter will be used in other chapters of Class 11 and Class 12 Physics.

3. What is the difference between Work Energy and Power studied in Class 9 and Class 11 NCERT

In Class 11 more analysis is done using Mathematics (vector and calculus) and some more concepts are added. The concepts of collision is not explained in the Class 9 NCERT Science book.

4. How to work energy and power class 11 ncert pdf

To download the PDF version of work energy and power class 11 solutions click on NCERT Solutions for Class 11 Physics and select the chapter according to your comfort and click on the download PDF.

5. What are collisions covered in class 11 physics work energy and power?

A collision is an event that happens when two objects come into direct contact with each other and exert forces on each other for a relatively short period of time. This can involve two or more bodies interacting with one another, resulting in changes in their motion and momentum.

Get answers from students and experts

Get up to 90% scholarship on NEET, JEE & Foundation courses

Register FREE for ALLEN Digital Scholarship Admission Test (ADSAT)

As per latest 2024 syllabus. Physics formulas, equations, & laws of class 11 & 12th chapters

Enrol in PW Vidyapeeth center for JEE coaching

As per latest 2024 syllabus. Chemistry formulas, equations, & laws of class 11 & 12th chapters

Start your JEE preparation with ALLEN

News and Notifications

08/06/2024, 10:30:42

05/06/2024, 15:32:39

05/06/2024, 09:36:45

04/06/2024, 03:18:06

03/06/2024, 13:08:59

03/06/2024, 11:09:02

Back to top