**What is the difference between Work, Energy and Power: Class 9 CBSE**

What is the difference between Work, Energy, and Power Class 9 CBSE: Work is the product of force and displacement in the direction of force, energy is the efficiency of doing work and power is the rate of doing work or the rate of consumption of the energy.Here the detail of the physics terms, Work, Energy, and Power are explained beautifully so that each student could understand basic physics concepts clearly before upgrading to the higher class physics.

You can study here

- Definition of the work
- The formula of the work
- Unit of work
- Example of work
- Definition of the Energy
- The formula of the Energy
- Unit of Energy
- Example of Energy
- Work-Energy Theorem
- Definition of the power
- The formula of the power
- Unit of power
- Example of power

**Work Definition: **

The work is the product of the force and displacement in the direction of the force or the component of the force,for the complete definition of work, force should be replaced by the component of the force, since force, as well as displacement both, are vector quantities the angle between force and displacement may be 0° to 90°, therefore, one component of force displaces the object in the direction of the force.

In real life the meaning of work is quite different, for example, if somebody is working on a computer then scientifically there is no work done because the computer is not displaced by the worker.

**The formula of the work:**

Where W is the work done and Fcosθ is the component of the force in the direction of the displacement and d is displacement.

Class 9 students of CBSE are required to remember only that

W= F×d

**Unit of work:**

The formula for the work is

W = F.d

The unit of the work done = Unit of the force× Unit of the displacement= Nm(Newton meter) =Joule

1NM is named 1 joule after the name of James Prescott Joule who discovered the relationship between mechanical work and heat transfer.

### Example of work

A force of 50 N on an object displaces it up to the distance of 5m in the direction of the force, find the work done on the object.

Solution:F= 50 N, d = 5 m

W = F.d = 50 ×5 = 250 J

**Definition of the Energy:**

Energy is the efficiency or capacity of the doing work, energy has different forms, energy is neither created nor destroyed, and it can be changed from one form to another form. It can also be defined as a transfer of the work.

**The formula of Energy: **

There are several types of energy for example mechanical energy, chemical energy, nuclear energy, gravitational energy, etc.

Here we shall discuss the formula of mechanical energy which is of two types

**Kinetic energy**: Kinetic energy is the capacity to do work by a moving object

Let the mass of the object is m and its velocity is v then kinetic energy is given by

**Potential energy:** Potential energy is the capacity of doing work by a stationary body due to its specific position.

Let the mass of the object is m and it is displaced to a certain height(h) from the ground of the earth then its potential energy is given by

**Unit of Energy:**

The unit of energy is the joule same as that of work done

**Example of Energy:** An object of the mass 50 gm is moving with a velocity of 10 m/s , finds its kinetic energy.

Solution: The kinetic energy of the object is given by

Where m = 50 gm = (50/1000) kg = 0.05 kg and v = 10 m/s

Hence the kinetic energy of the object is 0.25 Joule

**Work Energy Theorem:** Work is the transfer of the energy,the work done is stored in the form of energy,both work done and energy are interconvertible to each other.The amount of work done depends on how much energy is supplied for doing work.

Let work done is W and energy transfer is ΔE

W = ΔE

**Definition of the power:**

Power is the rate of doing work or the rate of the amount of energy released or consumed. Power is measured as the extent of work done within a given time.

**The formula of the power**

The power (P) = Work/Time

P = W/T

**Unit of power**

The SI unit of the power is a watt

1 watt =1 Joul/second

**Example of power**

A bulb of 100 w is kept on up to the time of 5h, then how much work is done by it or energy consumed by it.

Solution: P= W/T

T = 5h=5×60×60 = 1800s, P= 100 W

100 = W/1800

W= 180000 J

**Class 9 Physics Important Notes**

**Average Speed and Average velocity**

**The universal law of gravitational force**

**Thrust and Pressure : Difference**

**Archimedes Principle: Complete detail**

**CBSE IX Class Science Sample Papers**

**Class 9 Chemistry Important Notes**

**Evoporation,Vapourization and Latent heat**

**How does the water kept in an earthen pot become cold during summer?**

**What are the factors affecting evaporation?,**

**What is the difference between solution,colloid and suspension?**

**What is the difference between element and the compound?**

**Determining Valency, Net Charge and Molecular Formula**

**Molar mass,molecular mass and mole concept**

**If energy is conserved then why do we need to save it for future generations?**

**Class 9 ****Biology Important Notes**

**Structure and Function of Cell : Cell Biology**

**Types of plant tissues : Class 9 CBSE Notes**

**Animal Tissues : Class 9 Science CBSE**

**Class 9 Science previous years Question papers with solutions and important questions and answers**

**CBSE Class 9-Question paper of science 2020 with solutions**

**CBSE Class 9-Sample paper of science**

**CBSE Class 9-Unsolved question paper of science 2019**

**Click the link for NCERT Solutions for classes 9,10,11 and 12 of Maths & Science**

**NCERT Solutions and CBSE notes for Class 9,10,11 and 12 of Maths and Science**

**NCERT Solutions of Class 9 Science : Chapter 1 to Chapter 15**

**NCERT Solutions of Class 9 Maths : from chapter 1 to 15**

**NCERT Solutions Class 10 Science from chapter 1 to 16**

**NCERT Solutions of all chapters of Maths for Class 10 from Chapters 1 to 15**

**NEET Syllabus and its preparation**

**Specific notes for the preparation of 10 class CBSE board exam for achieving excellent marks**

**What to do to pass in maths CBSE X th board exam ?**

**Tips to get success in competitive exams**

**NCERT Solutions of class 9 science **