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1.Simple machine, any of several devices with few or no moving parts that are used to modify motion and the magnitude of a force in order to perform work
..Simple machines are useful because they reduce effort or extend the ability of people to perform tasks beyond their normal capabilities. Simple machines that are widely used include the wheel and axle, pulley, inclined plane, screw, wedge and lever.
2.Artificial satellites are used to study the Earth, other planets, to help us communicate, and even to observe the distant Universe. Satellites can even have people in them, like the International Space Station and the Space Shuttle.
3.Mineral like copper is used in electrical equipments as it is good electrical conductor. Clay is used to make cement etc which helps in constructing roads. Fibreglass, cleaning agents are made by borax.
4.Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, dust, pollen and mold spores may be suspended as particles. Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's also called smog. Some air pollutants are poisonous.
Causes of air pollution:-
suspended particles, smogs...
gases release from industries
the fuel gases.
5.In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is forme.
6.In the sedimentation process, heavier components of the mixture settle on the bottom, due to gravity. Decantation follows sedimentation. The decantation process involves pouring clear, upper liquid out of the container, without disturbing the sediment.