Gravitation

Gravitational force between two point masses

F=GMm/r^2

Gravitational field strength

 distance at a point in gravitational field is defined as gravitational force per unit massE=F/m

Gravitational potential

Gravitational potential at a point in a gravitational field is defined as negative of work done by gravitational force in moving a unit mass from infinity to that pointV=GM/r

Gravitational Potential energy

It is the negative of work done by gravitational forces in making the system from infinite separation to the present position

U=-GMm/r

Escape velocity

It is the velocity at which an object is thrown so that it can cross out the gravitational attraction of earth and reaches into the Vacuum 

Escape Velocity= √(2gR) = √(2GM/R)=11.2 km/s

Orbital Velocity The velocity with which an object is revolving around a planet in Space

 Orbital velocity= √GM/r

Kepler's Law

He gave three empirical laws which describes the motion of planets

First law

Each planet moves in an elliptical orbit with the sun at one focus of the ellipse

Second Law

The radius vector drawn from the sun to the planet sweeps out equal areas in equal interval of time that is aerial velocity is constant

dA/dt=L/2m= constant

Where L is angular momentum and m is the mass of the planet

Third Law

T^2=r^3

Square of the period of revolution of a planet around the sun is always proportional to the cube of the distance of a planet from the sun

Mon Nov 28, 2022