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In today’s Basic Science class, We will be discussing Energy Transfer when Work is Done. We hope you enjoy the class!
TOPIC: ENERGY TRANSFER WHEN WORK IS DONE
There is a major principle of energy which states that energy cannot be created nor destroyed but can be converted from one form to another. We have treated the forms of energy briefly in the preceding lessons. For the purpose of refreshing your memory, they are mechanical energy, light energy, sound energy, electrical energy, heat energy, nuclear energy, magnetic energy, chemical energy and solar energy. All these forms of energy are very vital in our daily activities as humans.
Work represents the transfer of energy in a mechanical system. There are many forms of energy, but what relates them all is that when they are transformed from one form to another, the total amount remains the same. If an object of mass m, initially at rest from a point is allowed to fall freely by gravity on the ground. The energy at that point is completely in the form of potential energy, mgh. The object acquired kinetic energy while falling. The kinetic energy increases and potential energy decreases. At the end of the motion, that is, when the object hit the ground, the energy is totally kinetic. The kinetic energy possessed by the object is equal to the initial potential energy, between the maximum height and the ground, the object possesses both kinetic energy and potential energy.
In a motorcycle, the chemical potential energy of the fuel changes to kinetic energy. When a person exerts a force on the wheelbarrow that is initially at rest, the wheelbarrow will be set in motion, thereby possessing kinetic energy. But where did the wheelbarrow get its kinetic energy? It came from the person exerting the force, who used chemical energy stored in the food the person ate to move the wheelbarrow. In other words, when the person did work on the wheelbarrow, they transferred a certain amount of chemical energy stored in the person to the wheelbarrow, causing it to gain kinetic energy. As a result, the person’s store of chemical energy decreases and the wheelbarrow’s kinetic energy increases. Another instance is when you kick a football. Chemical energy in the food you have eaten changes into mechanical energy in moving your legs and foot. When your foot kicks the ball, it gives kinetic energy to the ball which moves a distance before it eventually stops.
The kinetic energy of the moving air can be used to do work on the blades of a turbine at a wind farm. The energy gives the air particles the ability to apply a force and cause a displacement of the blades. As the blades turn, their energy is subsequently converted into electrical energy and supplied to homes and industries in order to run electrical appliances. Also, electricity supply from the mains is converted by an electric bulb into light (which can be seen) and heat (which can be felt).
We have come to the end of this class. We do hope you enjoyed the class?
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In our next class, we will be talking about Family Education. We are very much eager to meet you there.
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