20 Amazing Tricks of Archimedes Principle

Floatation:

Buoyant Force: When a body is immersed partly or wholly in a liquid, a force acts on the body by the liquid in the upward direction. This force is called buoyant force or upthrust. It is equal to the weight of liquid displaced by the body and acts at the centre of gravity of displaced liquid. Its study was first made by Archimedes.

20 Amazing Tricks of Archimedes Principle

Archimedes Principle: When a body is immersed partly or wholly in a liquid, there is an apparent loss in the weight of the body which is equal to the weight of liquid displaced by the body.
Law of Floatation: A body floats in a liquid if
Density of material of body is less than or equal to the density of liquid.
If density of material of body is equal to density of liquid, the body floats fully submerged in liquid in neutral equilibrium.
When body floats in neutral equilibrium, the weight of the body is equal to the weight of displaced liquid.
The centre of gravity of the body and centre of gravity of the displaced liquid should be in one vertical line.
Density: Density is defined as mass per unit volume. Density = mass / volume. Its SI unit is kg/m³.
Relative density = density of material / density of water at 4⁰C

20 Amazing Tricks of Archimedes Principle

Since relative density is a ratio, it is unitless.
Relative density is measured by Hydrometer.
The density of sea water is more than that of normal water. This explains why it is easier to swim in sea water.
When ice floats in water, its 1/10 part remain outside the water.
If ice floating in water in a vessel melts,the level of water in the vessel does not change.

20 Amazing Tricks of Archimedes Principle

What is Satellite ?

Satellite :
Satellites are natural or artificial bodies revolving around a planet under its gravitational attraction. Moon is a natural satellite while INSAT-IB is an artificial satellite of earth.

20 Amazing Tricks of Archimedes Principle

Orbital speed of a satellite :
Orbital speed of a satellite is independent of its mass. Hence satellites of different masses revolving in the orbit of same radius have same orbital speed.
Orbital speed of a satellite depends upon the radius of orbit (height of satellite from the surface of earth).Greater the radius of orbit, lesser will be the orbital speed.
The orbital speed of a satellite revolving near the surface of earth is 7.9 km/sec.
Period of revolution of a satellite :
Time taken by a satellite to complete one revolution in its orbit is called its period of revolution.
Period of revolution = circumference of orbit/orbital speed.

20 Amazing Tricks of Archimedes Principle

Period of revolution of a satellite depends upon the height of satellite from the surface of earth. Greater the height, more will be the period of revolution.
Period of revolution of a satellite is independent of its mass.
The period of revolution of satellite revolving near the surface of earth is 1 hour 24 minutes.

20 Amazing Tricks of Archimedes Principle

Geo-Stationary satellite :
If a satellite revolves in equatorial plane in the direction of earth’s rotation i.e from west to east with a period of revolution equal to time period of rotation of earth on its own axis i.e 24 hours then the satellite will appear stationary relative to earth. Such a satellite is called Geo-stationary satellite.
Such a satellite revolves around the earth at a height of 36000 km. The orbit of Geo-stationary satellite is called parking orbit. Arthur C. Clarck was first to predict that a communication satellite can be stationed in the geosynchronous orbit.

20 Amazing Tricks of Archimedes Principle

Escape velocity :
It is that minimum velocity with which a body should be projected from the surface of earth so as it goes out of gravitational field of earth and never return to earth.
Escape velocity is independent of the mass, shape and size of the body and its direction of projection.
Escape velocity is also called second cosmic velocity.
For earth, escape velocity = 11.2 km/s.
For moon, escape velocity = 2.4 km/s.
Orbital velocity of a satellite V_O= √(gR) and escape velocity Ve = √(2gR)
So we can say that escape velocity is √2 times the orbital velocity.
Therefore if the orbital velocity of a satellite is increased to √2 times (41%),the satellite will leave the orbit and escape.