Couple

Couple:

Angular Momentum

Angular Momentum

Torque

Torque

Equilibrium

Equilibrium

Intro- System of Particles and Rotational Motion

Rotational Motion

Gravitational Potential

Different energies of a Satellite

Time period and Height of satellite

Orbital and escape velocity

Orbital Velocity:

Orbital Velocity is the Velocity which is sufficient to cause a natural or artificial satellite to remain in orbit. The more massive the body at the centre of attraction, the higher is the orbital velocity

Escape Velocity:

Escape Velocity is the minimum velocity required for a free object to escape from the gravitational influence of a massive body.

Variation in 'g'

The gravity of a planet varies greatly and it is a quantity which depends mainly upon:

• Density
• Height from the surface
• Depth from the surface

Let us see how:-

Variation with Density:

Gravity ∝ Density

Variation with Height:

gₕ=(1-(2h/R))g

Variation with Depth:

gᵦ= (1-(d/R))g

Acceleration due to Gravity

The acceleration which is gained by an object when under the influence of Gravity is known as Acceleration Due to Gravity. Its SI unit is m/s². It is a Vector quantity which means that it has both a magnitude and a direction. The Acceleration due to gravity on the surface of earth is represented as 'g'.

Universal Law of Gravitation

The Gravitational Constant, denoted buy the letter G, is an empirical physical constant used in the calculation of gravitational effects in Sir Issac Newton's law of Universal Gravitation.

Sir Issac Newton

Characteristics of 'G':

-It is always constant

-it is independent of mass of falling body

-It is a weak, long range force

-It always acts in action and reaction pair

-It is a centre force (works bw centre of mass of 2 bodies)

Gravity exerts a force on 2 bodies having mass which can be denoted as follows:

Intro to the chapter - Gravitation

The Story of Gravity first came into existence when a Greek mathematician, Geographer,Astrologer and Astronomer, Ptolemy,  considered the Earth to be the center of the universe and believed that all other Celestial bodies Revolved around the Earth.

Ptolemy

Ptolemaic System

Nicolaus Copernicus

It was much later in 1543 that the famous mathematician Nicolaus Copernicus formulated a model of the universe that placed the Sun rather than the Earth at the center of the universe. His theory is now known as Heliocentric Theory.
This theory was later proved mathematically by a Danish astronomer, Tycho Brake.

Johannes Kepler

Johannes Kepler played a key role in the 17th Century Scientific Revolution.
He gave 3 laws which are Very important from examination point of view.

-Law of Orbit

-Law of Area

-Law of Time Period

Law of Orbit

Law of Area

Law of Time Period