## Saturday, April 30, 2016

### Gravitation Complete Lesson

Gravitational force exits between every two bodies of the universe and it is directly proportional to the product of masses of the bodies and is inversely proportional to the square of distance of separation. This a universal law called Newton's law of gravitation. According to this law, the force is always attractive and it is independent of the medium existing between the two bodies. Thus the proportionality constant is constant over the entire universe.

The gravitational force between any two bodies is independent of the presence of the third body between them. When multiple bodies are present around any body, we can find the resultant force using the vector laws of addition.

We also know that gravitation varies with height, depth and location of the body on the earth. We have derived mathematical equations for each of the case in the respective post.

The body on the surface of the earth possess both potential and kinetic energy and it can be measured from the center of the earth as a reference.

The body rotating in a specific orbit will have some velocity and it is called orbital velocity. The minimum velocity required to be give n to a body so that it can escape from the influence of the earth is called escape velocity and equations are derived for each of them in the following video lessons as mentioned below.

### Gravitational Force of Attraction and Newton's Law

Orbital Velocity and Escape Velocity

### Gravitation Problems with Solutions Four

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