# Chapter 6 – Work, Energy and Power

The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:

Introduction

One of the most quintessential lessons in physics is work, energy, and power. Work is defined when the body produces displacement, power is a rate at which work can be done and energy is the vigor of the body to do work. The SI unit of energy and work is Joule, and the SI unit of power is Watt. So we discuss Work, Energy, and Power. We hope that you can revise and make insightful notes for your exams.

#### Kinetic Energy

The energy of an object that it acquires due to its motion is called kinetic energy. It has magnitude and no directions. Formula for kinetic energy is:

KE = ½ mv2

Where,

• KE = the kinetic energy
• m = the mass
• v = velocity

Work Done by a Variable Force

Forces that we experience in our everyday life are called variable forces because they are variable and subject to change. If there is a displacement in the system due to the application of the force then, it will be called as Work Done By a Variable Force. It can be calculated as:

Fs = -kx

Where,

• k =   the spring constant
• x = the displacement of the object

The Work-Energy Theorem for a Variable Force

This theorem is extracted from Newton’s second law. It expresses that the work done by the aggregate of all powers following up on a molecule approaches the adjustment in the kinetic energy of the molecule.

#### The Concept of Potential Energy

The energy that is caused by the object due to change in its positions is called potential energy. It depends on the force on both the objects. In other words, it is the energy produced due to the alteration of the stances. It can be constituted as:

W = m×g×h = mgh

Where,

• m = the mass
• g = the acceleration
• h = the height (meters)

#### The Conservation of Mechanical Energy

Mechanical Energy is the aggregate of kinetic energy and potential energy in an object that is utilized to accomplish a specific work. As such, it depicts the energy of an object as a result of its movement or position, or both.

The Conservation of Mechanical Energy expresses that energy can’t be made nor destroyed, it may be changed, starting with one structure then onto the next if the powers working are conservative in nature.

#### The Potential Energy of a Spring

The energy that is stored due to the deformation of an elastic object. The potential energy of the spring increases due to the work that is done is stretched out. The formula is:

P.E = ½ k x2

Where,

• k = the spring constant
• x = the spring displacement

#### Various Forms of Energy The Law of Conservation of Energy

• Heat Energy- Energy produced due to the accumulation of kinetic energy in any particle. If you keep a hot water glass for some time, it gets cooled down. It is due to the loss of heat energy.
• Chemical Energy- It is the energy that is stored in chemical compounds. At the point when a chemical reaction happens, there is an adjustment in the plane of particles which results in either retention (endothermic) or a delivery (exothermic) of energy.
• Electrical Energy- At the point when energy is created by kinetic energy because of moving electrical charges, it is called electrical energy. Electric eels and batteries are the ideal instances of electrical energy.
• Nuclear Energy – Nuclear energy is the energy that is present in the nucleus of an atom that is at the time of nuclear fusion and reaction, the energy that is churned out. The classic example of nuclear energy is Hiroshima and Nagasaki’s malady.

#### Collisions

When an object comes in direct contact with others and force is wielded between the objects, it is called collisions. The two types of collisions are:

• Elastic collisions – A collision due to no net loss of kinetic energy.
• Inelastic collisions – A collision due to the loss of kinetic energy.

1. What is work power and energy in physics?

These are widely used terms in Physics:

• When there is any movement in objects due to some external force, it is called work.
• Power is your rate at which you do your work. It’s a scalar quantity as it doesn’t follow any direction.
• Energy is defined as your ability to work or your potential to do any activity.

2. What is the difference between work power and energy?

WorkPowerEnergy
Work depends on the displacementPower depends on the timeEnergy neither depends on time nor on displacement.
It refers to force appliedIt refers to work done per unit of timeIt refers to other factors like heat

3. What are the two types of Energy?

The two types of energy are:

• Kinetic Energy- The energy that objects possess due to its motion.
• Potential Energy- The energy that can be easily stowed.

4. Can kinetic energy of a body be negative?

No, the kinetic energy of a body can’t be negative because mass and square of speed can never be negative. Indeed, the change in kinetic energy can be negative.

Work, Energy, and Power is the first and foremost chapter in Physics that needs to be thoroughly studied to comprehend the concepts better. You need to have detailed information and a critical understanding of formulae. To get detailed information, you can check out videos on MSVgo. MSVgo is an e-learning app which has been developed to embark conceptual learning in the students from grade 6-12. MSVgo has been providing the students with a core understanding of the concepts. I It is an app with a video library that explains concepts with examples or explanatory visualizations or animations. Watch, Learn, and Grow!!

### High School Physics

• Alternating Current
• Atoms
• Communication Systems
• Current Electricity
• Dual nature of Radiation and Matter
• Electric Charges and Fields
• Electricity
• Electromagnetic Induction
• Electromagnetic Waves
• Electrons and Photons
• Electrostatic Potential and Capacitance
• Fluid Pressure
• Force and Acceleration
• Force And Laws Of Motion
• Gravitation
• Internal Energy
• Kinetic Theory
• Law of motion
• Light – Reflection And Refraction
• Magnetic Effects Of Electric Current
• Magnetism and Matter
• Management Of Natural Resources
• Mechanical properties of Fluids
• Mechanical properties of Solids
• Motion
• Motion in a plane
• Motion in a straight line
• Moving Charges and Magnetism
• Nuclear Energy
• Nuclei
• Oscillations
• Our Environment
• Paths of Heat
• Physical world
• Ray optics and optical instruments
• Semiconductor Devices
• Semiconductor Electronics: Materials, Devices and Simple Circuits
• Simple Machines
• Sound
• Sources Of Energy
• Specific and Latent Heats
• Spherical Mirrors
• Static Electricity
• Systems of Particles and Rotational motion
• Thermal properties of matter
• Thermodynamics
• Units and Measurement
• Vectors, Scalar Quantities and Elementary Calculus
• Wave Optics
• Waves
• Work, Power and Energy

### High School Chemistry

• Acids, Bases and Salts
• Alcohols, Phenols and Ethers
• Aldehydes, Ketones and Carboxylic Acids
• Aliphatic and Aromatic Hydrocarbons
• Alkyl and Aryl Halides
• Amines
• Analytical Chemistry
• Atomic Structure
• Atoms And Molecules
• Basic concepts of Chemistry
• Biomolecules
• Carbon And Its Compounds
• Carboxylic acids and Acid Derivatives
• Chemical Bonding and Molecular Structures
• Chemical Energetics
• Chemical Equilibria
• Chemical Kinetics
• Chemical Reactions And Equations
• Chemical Reactions and Their Mechanisms
• Chemistry in Everyday Life
• Chemistry of p-Block elements
• Chemistry of Transition and Inner Transition
• Classification of Elements
• Coordination Compounds
• Cyanide, Isocyanide, Nitro compounds and Amines
• Electrochemistry
• Electrolysis
• Elements, Compounds and Mixtures
• Environmental Chemistry
• Equilibrium
• Ethers and Carbonyl compounds
• Haloalkanes and Haloarenes
• Hydrocarbons
• Hydrogen
• Ideal solutions
• Introduction to Organic Chemistry
• Ionic equilibria
• Matter
• Matter Around Us
• Matter In Our Surroundings
• Metallurgy
• Metals And Non-Metals
• Mole Concept and Stoichiometry
• Natural Resources
• Organic Chemistry – Basic Principles
• Periodic Classification of Elements
• Physical and Chemical Changes
• Physical and Chemical Properties of Water
• Polymers
• Preparation, Properties and Uses of Compounds
• Principles and Processes of Isolation of Elements
• Redox Reactions
• Relative Molecular Mass and Mole
• States of Matter
• Structure Of The Atom
• Study of Compounds
• Study of Gas Laws
• Study of Representative Elements
• Surface Chemistry
• The d-block and f-block elements
• The Gaseous State
• The p-Block Elements
• The Periodic Table
• The s-Block Elements
• The Solid State
• Thermodynamics

### High School Biology

• Absorption and Movement of Water in Plants
• Anatomy of Flowering Plants
• Animal Kingdom
• Bacteria and Fungi-Friends and Foe
• Biodiversity and Conservation
• Biofertilizers
• Biological Classification
• Biomedical Engineering
• Biomolecules
• Biotechnology and its Applications
• Biotic Community
• Body Fluids and Circulation
• Breathing and Exchange of Gases
• Cell – Unit of Life
• Cell Cycle and Cell Division
• Cell Division and Structure of Chromosomes
• Cell Reproduction
• Cellular Respiration
• Chemical Coordination and Integration
• Circulation
• Control And Coordination
• Crop Improvement
• Digestion and Absorption
• Diversity In Living Organisms
• Ecosystem
• Environmental Issues
• Excretory Products and their Elimination
• Flowering Plants
• Genes and Chromosomes
• Health and Diseases
• Health and Its Significance
• Heredity And Evolution
• Heredity and Variation
• How Do Organisms Reproduce?
• Human Diseases
• Human Eye And Colourful World
• Human Health and Disease
• Human Population
• Human Reproduction
• Hygiene
• Improvement In Food Resources
• Integumentary System- Skin
• Kingdom Fungi
• Kingdom Monera
• Kingdom Protista
• Life Processes
• Locomotion and Movement
• Microbes in Human Welfare
• Mineral Nutrition
• Molecular Basis of Inheritance
• Morphology of Flowering Plants
• Neural Control And Coordination
• Nutrition in Human Beings
• Organism and Population
• Photosynthesis
• Photosynthesis in Higher Plants
• Plant Growth and Development
• Plant Kingdom
• Pollination and Fertilization
• Pollution; Sources and its effects
• Principles of Inheritance and Variation
• Reproduction and Development in Angiosperms
• Reproduction in Organisms
• Reproductive Health
• Respiration in Human Beings
• Respiration in Plants
• Respiratory System
• Sexual Reproduction in Flowering Plants
• Strategies for Enhancement in Food Production
• Structural Organisation in Animals
• Structural Organisation of the Cell
• The Endocrine System
• The Fundamental Unit Of Life
• The Living World
• The Nervous System and Sense Organs
• Tissues
• Transpiration
• Transport in Plants

### High School Math

• Algebra – Arithmatic Progressions
• Algebra – Complex Numbers and Quadratic Equations
• Algebra – Linear Inequalities
• Algebra – Pair of Linear Equations in Two Variables
• Algebra – Polynomials
• Algebra – Principle of Mathematical Induction
• Binomial Theorem
• Calculus – Applications of Derivatives
• Calculus – Applications of the Integrals
• Calculus – Continuity and Differentiability
• Calculus – Differential Equations
• Calculus – Integrals
• Geometry – Area
• Geometry – Circles
• Geometry – Conic Sections
• Geometry – Constructions
• Geometry – Introduction to Euclid’s Geometry
• Geometry – Three-dimensional Geometry
• Geometry – Lines and Angles
• Geometry – Straight Lines
• Geometry – Triangles
• Linear Programming
• Matrices and Determinants
• Mensuration – Areas
• Mensuration – Surface Areas and Volumes
• Number Systems
• Number Systems – Real Numbers
• Permutations and Combinations
• Probability
• Sequence and Series
• Sets and Functions
• Statistics
• Trignometry – Height and Distance
• Trignometry – Identities
• Trignometry – Introduction

### Middle School Science

• Acids, Bases And Salts
• Air and Its Constituents
• Basic Biology
• Body Movements
• Carbon and Its Compounds
• Cell – Structure And Functions
• Changes Around Us
• Chemical Effects Of Electric Current
• Coal And Petroleum
• Combustion And Flame
• Components Of Food
• Conservation Of Plants And Animals
• Crop Production And Management
• Electric Current And Its Effects
• Electricity And Circuits
• Elements and Compounds
• Fibre To Fabric
• Food production and management
• Force And Pressure
• Forests: Our Lifeline
• Friction
• Fun With Magnets
• Garbage In, Garbage Out
• Getting To Know Plants
• Health and Hygiene
• Heat
• Hydrogen
• Life Processes: Nutrition in Animals and Plants
• Materials: Metals And Non-Metals
• Matter and Its States
• Metals and Non-metals
• Micro Organisms: Friend And Foe
• Motion And Measurement Of Distances
• Motion And Time
• Nutrition In Animals
• Nutrition In Plants
• Organization in Living Things
• Our Environment
• Physical And Chemical Changes
• Pollution and conservation
• Pollution Of Air And Water
• Reaching The Age Of Adolescence
• Reproduction In Animals
• Reproduction In Plants
• Respiration In Organisms
• Rocks and Minerals
• Separation Of Substances
• Simple Machines
• Soil
• Some Natural Phenomena
• Sorting Materials Into Groups
• Sound
• Stars And The Solar System
• Structure of Atom
• Synthetic Fibers And Plastics
• The Living Organisms And Their Surroundings
• Transfer of Heat
• Transformation of Substances
• Transportation In Animals And Plants
• Universe
• Waste-water Story
• Water: A Precious Resource
• Weather, Climate And Adaptations Of Animals To Climate
• Winds, Storms And Cyclones

### Middle School Math

• Area and Its Boundary
• Boxes and Sketches
• Data Handling
• Fun With Numbers
• Heavy and Light
• How Many
• Long And Short
• Mapping
• Measurement
• Money
• Multiplication and Factors
• Multiply and Divide
• Numbers
• Parts and Wholes
• Pattern Recognition
• Patterns
• Play With Patterns
• Rupees And Paise
• Shapes And Angles
• Shapes And Designs
• Shapes and Space
• Similarity
• Smart Charts
• Squares
• Subtraction
• Tables And Shares
• Tenths and Hundredths
• Time