Power is the rate at which work is done or energy is transformed. Work, energy and power definition, units, formula, examples. Important notes are also helpful for revision when you have less time and have to study many topics. Work done by a force in displacing a body is equal to change in its kinetic energy. Class 11 physics revision notes for chapter 6 work. Work, energy and power in this section of the transport unit, we will look at the energy changes that take place when a force acts upon an object. Work done is generally referred in relation to the force applied while energy is used in reference to other factors such as heat.
If the magnitude of the displacement of the object is labeled x, and this represents the displacement away from an equilibrium position x 0, then the force required to pull the object on the spring to a. Energy transformed work done applied force x distance. Workenergy theorem work, energy and power siyavula. The engine of your motorcycle works under this principle. Distance, velocity, momentum, force, pressure, work and.
Work is said to be done when a force applied to an object moves that. Work, energy and power physics neet class topperlearning. Suppose a force f acts on a body, causing it to move in a particular direction. Energy is a key principle in physics, as it allows work to be done. Understand the use and limitations of the bernoulli equation, and apply it to solve a variety of fluid flow problems. Energy cant be created or destroyed, it can only be changed from one type into another type. Work and kinetic energy formula, definition, equation. If youre seeing this message, it means were having trouble loading external resources on our website.
It is measured by the product of the force and the distance moved in. Work, energy and power definition, units, formula, examples, types. Work, power and efficiency work, power and efficiency aqa. The unit of kinetic energy is the same as the unit of work, the joule j. Energy onpage 157 we dealt with power arid noted that power is the rate at which energy is transferred from one place to another or from one form to another the formula that links energy and power is. Work, energy and power tuesday february 10th reading.
Distance, velocity, momentum, force, pressure, work and energy. Here are complete work energy and power important notes and summary. The terms work, energy and power are frequently used in everyday language. Physics 0303 nonconservative forces and conservation of energy. A powerful hoist needs energy fuel to keep on working. You can also call it as revision notes for work energy and power or cheat sheet of work energy and. For example, potential energy in the compressed spring, kinetic energy in the moving object, electromagnetic energy and heat are some of them. The rate at which energy is transferred is called power and the amount of energy that is usefully transferred is called efficiency. Work, energy and power formula list and important points in this video, we will revise the topic work, energy and power. This is because the object experiences an acceleration and therefore a change in velocity.
This also means the constraint forces do not add to the instantaneous power. Hvac formulas ton of refrigeration the amount of heat required to melt a ton 2000 lbs. The rate at which energy is transferred is called power and the amount of energy that. Product of force on an object and the distance through.
It is important to know whether a force is an conservative force or an nonconservative force in the system, because this is related to whether the force can change an objects total mechanical energy. There are many forms of energy, each involving both kinetic and potential energy. Work done by the force is negative if the angle between force and displacement is obtuse 90 work done is negative. Work formula example of work types of energy power formula questions. Jul 24, 2018 class 11 physics chapter 6 work, energy and power 03 work energy theorem iit jee neet duration. Cbse class 11 physics notes chapter 6 work energy and power. Work done by the force is equal to the product of the force and the displacement of the object in the direction of force. This summarizes most important formulae, concepts, in form of notes of work energy and power which you can read for jee, neet preparation. Work done by the force is positive if the angle between force and displacement is acute 0 feb 09, 2017 work, energy and power formula list and important points in this video, we will revise the topic work, energy and power. Choose from 500 different sets of science work power formulas flashcards on quizlet. Physics notes class 11 chapter 6 work, energy and power work when a force acts on an object and the object actually moves in the direction of force, then the work is said to be done by the force.
It is measured by the product of the force and the distance moved in the direction of the force, i. Joule the units of work, equivalent to a newtonmeter. The equation for power can be written as the rate of work. Work done w is defined as the dot product of force f and displacement s. Regarding the work energy theorem it is worth noting that i if w net is positive, then k f k i positive, i. A moving car, walking up stairs, lifting heavy objects, an airplane flying, etc are among the most common examples that give us insight into the concept of work, power, and energy. Static friction kinetic friction velocity addition centripetal acceleration. Power can also be defined as the rate of transfer of energy. The important notes of physics for work energy and power pdf download are available here for free. Work and kinetic energy formula, definition, equation, videos.
In other words, the work done is equal to the change in k. Work done is measured in joules which has symbol j. Mathematically, it is computed using the following equation. Learn science work power formulas with free interactive flashcards. Chapter 6 work, kinetic energy and potential energy. Mar 24, 2019 important notes of physics for neet, jee for work energy and power are useful for all aspirants preparing for entrance exams including jee, neet. For formulas, see work done by a constant force parallel to displacement and work done by any constant force, and work done by a positiondependent force. A farmer clearing weeds in his field is said to be working hard. Physics 0302 potential energy and conservative forces. A moving car, walking up stairs, lifting heavy objects, an aeroplane flying, etc are among the most common examples that give us insight into the concept of work, power, and energy. Cbse class 11 physics work, energy and power formulas. We can calculate work by multiplying the force by the movement of the object. The time integral of this scalar equation yields work from the instantaneous power, and kinetic energy from the scalar product of velocity and acceleration.
December 1996 subcourse overview this subcourse is designed to teach you to perform work, power and energy calculations for electrical circuits. The kinetic energy of an object can be related to its mass and velocity with the formula, this formula for kinetic energy can be found from the equation for work, if the force is in the same direction as the objects displacement. The unit of energy is the joule, the unit of power is the watt, and the unit of time is the second. The ratio of the kinetic energy gained to the work put in to lifting the cars is the efficiency kegpe of the system. Regarding the workenergy theorem it is worth noting that i if w net is positive, then k f k i positive, i. Derive an equation for the potential energy of a spring, using hookes law and a forcedisplacement graph. Energy energy is the quantity that can be used to perform work. If youre behind a web filter, please make sure that the domains. In grade 10, you saw that mechanical energy was conserved in the absence of nonconservative forces. Energy the capability of doing work is called energy.
Physics notes class 11 chapter 6 work, energy and power. In other words, the work done on an object is the change in its kinetic energy. Energy is the capacity of an object to transform the world which surrounds it. If negative work is done, then the object will lose energy. The further it moves under the influence of your force, the more work you perform. The bigger unit of power is kilowatt and represented by kw.
Work, energy and power formulae work of a constant force. A collision in which the total kinetic energy of the system is conserved is called elastic. Work, power, and energy electrical subcourse number it 0348 edition a us army intelligence center fort huachuca, az 8566000 2 credit hours edition date. The faster the pendulum bob moves, the greater its kinetic energy. In the international system of units, the unit of power is the watt, equal to one joule per second. Work with the energy equation expressed in terms of heads, and use it to determine turbine power output and pumping power requirements. P power watts, w, js u voltage volts, v i current amperes, a r resistance ohms. Doubling the speed quadruples the kinetic energy so the work by friction to reduce the kinetic energy to 0 make it stop must also increase by a factor of 4. Dimensions of power linear momentum of an isolated system is always conserved in a collision. Power, the rate at which work is done or energy is transferred into or out of the system. In physics, we can define energy as the capacity to do work. One example is the work required to stretch a spring. The work w done by the net force on a particle equals the change in the particles kinetic energy ke. The kinetic energy of an object can be related to its mass and velocity with the formula, this formula for kinetic energy can be found from the equation for work, if the force is.
Solved examples on work, power and energy study material for. These notes are prepared by some of the highly expert teachers. Note if power is more, work is done fast and vice versa. Using the estimates of kinetic energy from problem 3, calculate the efficiency energy in vs. An electric stove consumes 5 mj of energy from a 230 v power supply when turned on in 60 minutes.
This is the workenergy theorem or the relation between kinetic energy and work done. Then the work done by the force is the component of f in the direction of motion. Problem set overview this set of 32 problems targets your ability to use equations related to work and power, to calculate the kinetic, potential and total mechanical energy, and to use the work energy relationship in order to determine the final speed, stopping distance or final height of an object. The force and the displacement must be parallel to one another in order for work to be done. Work of a constant force force is parallel to displacement work of force of friction w f x cos w f x w ffric x kinetic energy 2 2 1 ek mv gravitational potential energy near a planet surface ep m g h gravitational potential energy r m m ep g elastic potential energy 2 2 1 ep k x. Also, we know that when an object in motion strikes a stationary object, it can cause it to move. If the puck slides twice as far, the friction does twice as much negative work. Kinetic energy is energy associated with motion, whether in a straight line of a circle. As is implied by the equation for power, a unit of power is equivalent to a unit of work divided by a unit of time. Class 11 physics revision notes for chapter 6 work, energy and power free pdf download. Cascarano formula sheet physics 4a foothill college. Work, energy and power class 11 notes physics chapter 6. When a net force does work on an object, then there is always a change in the kinetic energy of the object. Work w is the energy transferred to or from an object by means of a force acting on the object.
I will start the video by discussing calculation of dot product of two. There are two types of energy, kinetic and potential. If positive work is done, then the object will gain energy. Work definition if an object moves in response to your application of a force, you have performed work. A woman carrying water from a well to her house is said to be working. The power rating energy per unit time of the stove can be calculated as.
In the equation the mass is measured in kilograms and speed in ms. This section covers work, energy and power using maths. The fact that the work energy principle eliminates the constraint forces underlies lagrangian mechanics. Work is said to be done when a force applied to an object moves that object. Work, power and efficiency work, power and efficiency. In a drought affected region she may be required to carry it over large. Work can be used to understand the energy of many objects that experience forces. The energy dissipated in 60 seconds can be calculated. This article deals with the summary of work, power and energy, formulas and how they are related to each other in a crux form which not only clear your concepts but also help in your preparation. Work, power, and energy are among the most important concepts of mechanics. Kinetic energy of an object is its capacity to put another object in motion. In physics, power is the rate of doing work or of transferring heat, i. Introduction to work and energy video khan academy.
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