Gravitational Field Flashcards
What is the Newton’s law of gravitation?
Newton’s Law of Gravitation states that two point masses attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
What is a gravitational field?
It is a region of space in which a mass experiences a force due to the presence of another mass.
Define Gravitational Field Strength.
The gravitational field strength at a point in a gravitational field is defined as the gravitational force per unit mass acting on a test mass placed at that point.
Define gravitational potential energy.
The GPE U of a mass at a point in a gravitational field is defined as the work done by an external agent in bringing the mass from infinity to that point with constant speed.
Define gravitational potential.
The gravitational potential at a point in a gravitational field is defined as the work done per unit mass by an external agent in bringing a test mass from infinity to that point.
What is the shell theorem?
- A spherically symmetrical body affects external objects gravitationally as though all of its mass were concentrated at a point in its centre.
- If the body is spherically symmetrical shell, no net gravitational force is exerted by the shell on any object inside, regardless of the object’s location within the shell.
What is the Kepler’s third law?
Kepler’s third law states that the square of the period of revolution of the planets is directly proportional to the cubes of their mean distance from the Sun.
Advantages of a Geostationary Orbit.
- There is a continuous surveillance of the region under it.
- It is easy for the ground station to communicate with it as it is permanently within view.
- Due to the high altitude, the satellite can transmit and receive signals over a large area.
Disadvantages of a Geostationary Orbit.
- Significant loss of signal strength.
- Poorer resolution in imaging satellites.
- Time lag in telecommunication.
