GEO- POSITIONING SYSTEM

One fine morning, you wake up in the middle of dense forest. You do not know where you are? But luckily, you have a FM radio set. Tune the radio, you hear one station feebly. You know the location of that radio station. The maximum range of that FM station is 100 km (say). You must be at the edge of 100 km since the FM signals are weak. Now, you draw a circle with that radio station as the center and 100 km as radius. You must be somewhere on the edge of the circle.

Now try for another station. Luck favors you again. You get second station that too feebly. Now this station as center, you draw second circle of same radius. Now the two circles meet at two points. You may be on any one of the point. Still the information is not enough. Try your luck again. The God of luck is still with you. You get third FM station some what clearly. Draw third circle as usual. The three circles meet at one point. Thank God, that is your location. This is known as 'triangular method'. This technique is used in Geo-positioning system . (GPS)

There are 31 satellites in GPS orbits now. A minimum of 4 satellites will be in contact with GPS receiver you have. Each will send the signals to your receiver and get it back in milliseconds. Then the satellite calculate the distance between you and itself using the time. Next it will draw an imaginary sphere around it using calculated distance as radius. (No circles in space, only spheres)

You can be anywhere on the surface of the sphere. Each satellite will draw its own calculated sphere. Earth sphere can also ,be taken into account. Using the triangulation method you will be located accurately by GPS. That is, all the spheres will meet at one point where you are exactly located.

GPS now have accuracy of 5 meters. It will come down to centimeters in future.
GPS is the boon to modern day navigation.

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THE EARTH, A SUPER ORGANISM

JOIN MY COURSE: "Become a programmer in a day with python" A man called 'love lock' (what a name) proposed a theory called Gaia theory, named after Greek Goddess. It says, "Earth is a self-regulating organism like a human being. The organic life in it interacts with in-organic matter and maintains atmosphere, temperature and environment". Hence the earth is still suitable for the life to thrive. Imagine, in a particular place, there are lot of flowers. Some flowers are white and some are darkly coloured. We know, white reflects light and heat while dark absorbs the same. White flowers can thrive in hot climate. But dark flowers requires cold climate. The absorption and reflection balances and the environment reaches average, warm temperature at which both the flowers can co-exist. This is the essence of "Gaia" theory. On our earth, the oxygen constitute 20% of the atmosphere. The oxygen level is always mai

THE PARABOLA

A jet of water shooting from a hose pipe will follow a parabolic path. What is the so special about parabola. Y= x^2 Draw a graph for the above equation. It will result in a parabola. This parabola is also called unit parabola. Any equation involving square will yield a parabola. Example: Y = 2x^2 +3x+3 (also called quadratic equation) X= 2 and -2, both satisfies the equation 4 = X^2. Parabolic equations always have two solutions. Any motion taking place freely under gravity follows parabolic path. Examples: An object dropped from a moving train, A bomb dropped from flying plane, A ball kicked upwards. If a beam of light rays fall on the parabolic shaped mirror, they will be reflected and brought to focus on a point. This fact is made use of in Dish Antenna, Telescope mirrors, etc. Inverted parabola shape is used in the construction of buildings and bridges. Because the shape is able to bear more weight. A plane

DISORDER IS THE "ORDER OF THE DAY"

Imagine a balloon full of air. The air molecules are moving randomly inside the balloon. Let us pierce the balloon with a pin. The air rushes out. Why should not the air molecules stay inside the balloon safely and ignore the little hole? That is not the way the world works. The molecules always "want to occupy as many states as possible". Hence the air goes out in the open to occupy more volume. The things always goes into disorder (entropy) and the disorder increases with time. The above statement is what we call "second law of thermodynamics". Consider a cup of coffee on the table. Suppose the heat from entire room flows to your cup of coffee, the coffee will boil and the rest of the room will freeze. Freezing means bringing things to order and arrangement. It violates the second law. Hence it will never happen. Hence heat must flow from high temperature to low temperature and not the other way. The air molecules in y

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