Energy, power and work – these three are important parts of our life which not only help us in our day to day functioning but also explain how we work in the field of science and technology. Energy, Power and Work – These subjects give us an opportunity to study in the field of science and mathematics, so that we can understand deeply about these three. In this article, we will get detailed information about energy, power and work, understand their importance, and how they can be used in different situations.
concept of work
Work is generally called the process or activity which changes the state of an object. This item may potentially change as comfortable, necessary, or inappropriate. In other words, to do work, a force must be applied and there must be motion or displacement in the direction of the force. The work done by a force acting on an object is equal to the magnitude of the force multiplied by the distance moved in the direction of the force.
For example, when a person digs a wall, work is done to change the position of the wall. Here, digging in the wall is the act, which causes change in the position of the wall.
Formula and unit of work
The work done by a force depends on two factors:
- amount of force
- Distance (through which the object moves in the direction of the force)
Therefore, work is measured by the product of the force and the displacement of the object in the direction of the force. Work has only quantity, no direction. Hence work is a scalar quantity. The SI unit of work is joule (J).
Work = Force
To understand more deeply, the work done by a force is defined as the product of the component of the force in the direction of displacement (horizontal component) and the magnitude of this displacement. When an object is displaced by a force F by applying it to a distance S, then
Work (W) = FXS = F . S Cosθ
Where θ = angle between force and displacement.
concept of energy
Energy is generally defined as the ability to do work or work. It is the concentration, power, or movement of some kind that results from or is associated with bringing about a process or change. in other words Energy is the ability to do work. Example: Motion energy, energy capture, energy production, energy storage, energy utilization, etc.
Type of energy
Some other types of energy are given below:
- mechanical energy
- mechanical wave energy
- chemical energy
- electrical energy
- magnetic energy
- radiation energy
- nuclear energy
- ionization energy
- elastic energy
- gravitational energy
- thermal energy
- heat energy
Energy formulas and units
The energy generated by the work done by an object on itself is called mechanical energy. There are two types:
Potential Energy (PE)
Potential energy is a type of induced energy that an object has in its position. This means that the ability to do work in an object due to its location or shape or the energy generated in an object due to its position or shape is called potential energy. For example – energy of a compressed thread, energy of water collected at a height, energy of a spring in a clock etc. Potential energy of an object in the gravitational field of the earth.
PE = mxgxh
where m = mass
g = acceleration due to gravity
h = height of the object from the earth's surface.
kinetic energy (KE)
The energy generated in an object due to its motion is called kinetic energy. If an object of mass m is moving with speed v, then the kinetic energy of the object is
KE = (1/2)mv^{2}
Energy is a scalar quantity, that is, it has only magnitude and no direction. Its SI unit is joule. The unit of work or energy, Joule, is named after the British physicist “James Prescott Joule”.
concept of power
Power is a physical concept that has many different meanings depending on the context and available information. We can define power as the rate of doing work, and it is the amount of energy expended per unit time.
formula and unit of power
Power is the rate of doing work. Therefore, it can be calculated by dividing the work done by time. The formula for power is given below.
Power (P) = work done / time taken to do the work = W / t
Additionally, doing work requires an amount of energy equal to the work done. Therefore, power is also defined as the rate of expenditure or utilization of energy.
Power (P) = Energy consumption/ Time taken to consume energy = E/t
Because power has no direction, it is a scalar quantity. The SI unit of power is the joule per second (J/s), also called the watt.
other units of power
- 1 watt = 1 joule/second
- 1 kilowatt (KW) = 10^{3} Watt
- 1 megawatt (MW) = 10^{6} Watt
- 1 Horse power = 746 Watts = 0.75 KW
- 1 watt second = 1 watt x 1 second
- 1 watt hour (Wh) = 3600 joules
- 1 kilowatt hour (kWh) = 3.6 x 10^{6} joule
principle of energy conservation
Energy can neither be created nor destroyed, and can only be converted from one form to another.
energy of transformation some equipment
equipment | energy conversion of |
dynamo | mechanical energy into electrical energy |
Candle | chemical energy into light and heat energy |
microphone | sound energy into electrical energy |
loudspeaker | electrical energy into sound energy |
solar cell | solar energy/light energy into electrical energy |
Tube light | Electrical energy into light energy and heat energy |
electric bulb | Electrical energy into light energy and heat energy |
battery | chemical energy into electrical energy |
electric motor | electrical energy into mechanical energy |
Sitar | mechanical energy into sound energy |
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