# Chapter 4 – Energy

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

Introduction

There is a connection between diet and sleep. It is the energy that gives our bodies the power to stay healthy during day-to-day activities. You can climb, sprint, play, shout or do anything that moves your body, or even use your brain. These activities involve energy that can be measured to estimate how long it takes to do most things we do with our bodies, like running, jumping or riding a bike.

#### What is Energy?

Living creatures seek energy to sustain life, where human civilization needs the energy to work obtained from sources such as fossil oil, nuclear power or solar energy. Also, the planet’s atmosphere and ecological cycles are powered by Earth’s radiant and geothermal energy.

Energy is the quantitative property of physics that must be applied to an object to operate on it or heat it. Energy is a conserved quantity. The law of conservation of energy states that energy can neither be created nor destroyed but can only be converted from one form to another. The SI unit of energy is Joule.

#### Law of Conservation of Energy

One of the fundamental principles of physics is the law of energy conservation. In a chemical reaction, it controls the microscopic motion of individual atoms. According to the law, “In a closed system, i.e., a system that is isolated from its surroundings, the total energy of the system is conserved.” The law states that, even if energy transformation occurs, the whole energy is conserved in a system. Energy cannot be generated or lost; it can only get transformed from one form to another.

#### Different Forms of Energy

While several forms of energy exist, they are generally classified into kinetic energy and potential energy.

• Kinetic energy
The kinetic energy of an entity in physics is the energy it has due to its motion. It is classified as the work required to drive a specific mass body from rest to its specified velocity. After gaining this energy through its acceleration, the kinetic energy is maintained by the body without changing its rate. As the body decelerates from its current pace to a state of rest, it does the same amount of work it has done while going to that pace from rest.The kinetic energy of an object at motion is given by:K.E = ½ mv², where m is the object’s mass while v is the speed with which it moves.

The S.I. unit of kinetic energy is Joule, whereas the English engineering unit is foot-pound.

• Potential energy
The potential energy in physics is an object’s energy regardless of its location concerning other things, pressures, electrical charges, or other variables within it. Potential energy correlates with forces acting on a body, such that their overall work on the body only depends on the original and final locations of the body in place.Potential energy is further categorized into two different types: gravitational potential energy and elastic potential energy. Gravitational energy potential is an energy in an object which is retained vertically because of the gravitational force that works to bring it down. Elastic potential energy means energy in items, such as trampolines, rubber stripes and bungee cords, which can be extended or compressed. The longer an entity can spread, the more elastic energy it possesses.The potential energy formula relies on the force that works on different bodies. For the gravitational force, the formula is P.E. = mgh, where m is the mass in kilograms, g is the acceleration due to gravity (9.8 m / s² the Earth’s surface), and h is the height in meters.

#### Concept of Work

The concept of work is somewhat smaller than the usual definition of the word. Work on an object is achieved as the force applied pushes it across a path. An individual holding a heavyweight does not work because the force does not move the item from a distance.

In our daily language, the work done is attributed to muscle effort in doing a particular task, while this is not the case with physics. According to the physical definition, work is carried out as the heavyweight is moved from a stationary position.

The SI unit of work is known as Joule (J), named after the English physicist James Prescott Joule from the 19th century, which is now described as the work needed to generate a displacement of one metre by exerting a force of one Newton.

#### What is Power?

Like energy, we hear a lot about the word power. There are some differences between energy and power. It has a broad multitude of interpretations in daily life. But it has a unique significance in physics, where the rate at which work is done is defined as power.

Power often depends on work; even if a person works at various rates, his power varies at specific intervals. Here the principle of average power is taken into consideration.

The average power can be defined as the total consumption of energy divided by the entire time. In simple words, we can conclude that average power is the average work per unit of time. The rate at which work is performed on an item is known as power, and it is a quantity dependent on time. That’s how quickly a job is done. The powder formula is expressed as:

Power = Work done/ Time taken to complete the work or P = W/t

The S.I unit of power is joule/ second.

#### Energy Transformation

Energy transfer refers to energy flow from one spot to another. In contrast, energy transformation in common daily life situations involves energy change from one type to another, for example, from kinetic energy to energy or from potential energy to kinetic energy. Some examples of energy transformation are:

• The energy to move from one place to another is achieved by converting food’s chemical energy into mechanical energy.
• The phenomenon of lightning converts electrical energy into light, sound and heat energy.

#### Conclusion

For life and other living things, energy is crucially important. The sun is the origin of all the life on Earth, either directly or indirectly. It is vital to choose our energy sources carefully to influence our natural systems on Earth in ways we are maybe uncertain of.

#### FAQs

1. Why is renewable energy so important?
When the whole life cycle of technology is taken into account, specific renewable energy sources result in little to no pollution. No or low air pollutants generate green energy.
2. What is the difference between energy and power?
The fundamental difference between energy and power is that energy seems to be what changes are happening that can be transferred through one component. In contrast, power is the rate at which energy is transmitted.
3. How is energy generated?
Steam turbines produce much energy with fossil fuels, thorium reactors, biofuels, hydroelectric, and solar power energy.
4. How is work calculated in simple cases?
The calculation of work done in simple cases is by the formula,Work = Force x Distance.

To know more about energy in detail, you can download the MSVgo app for some explanatory videos and animations. Along with learning videos, you can also access interactive games and quizzes on the app.

### 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