Gravitation

- Are you finding the topics tough? Here is the extremely simple explanation
1
To learn the variation in value of 'g' due to change in altitude:
Acceleration due to gravity and its variation with height
9 mins
To understand the Gravitational potential and the gravitational potential energy:
Gravitational potential and gravitational potential energy: from fizzics.org
5 mins
2
Gravity near the earth
We can apply the Universal Law of Gravitation to objects near the earth also. For an object at or near the surface of the earth, the force due to gravity acts toward the center of the earth. That is, it acts downwards because every particle in the earth is attracting the object. The magnitude of the force on an object of mass m is given by:
where is the radius of the earth and is the mass of earth.
Let us calculate the constant
Viewing g as the value of Earth's gravitational field near the surface | Khan Academy
8 mins
3
How do satellites stay in orbit around earth?
Satellites are able to orbit around the planet because they are locked into speeds that are fast enough to defeat the downward pull of gravity. Satellites are sent into space by a rocket launched from the ground with enough energy (at least 25,039 mph) to get outside our atmosphere. Once the rocket reaches its determined location it drops the satellite into its orbit. The initial speed of the satellite maintained as it detaches from the launch vehicle is enough to keep a satellite on orbit for hundreds of years.
Binding Energy can be defined as the minimum energy required to be supplied to it order to free the satellite from the gravitational influence of the planet. (i.e; in order to take the satellite from the orbit to as point if infinity.) Hence Binding energy of satellite mass revolving around a planet of mass in a radius .
Escape velocity of satellites,
Why Don't Satellites Fall Out of the Sky?
3 mins