Gravitational Fields Flashcards
What is a gravitational field?
The region around a body in which other bodies will feel a force due to the mass of the body.
What are gravitational field lines?
Lines that show the shape of the field and the direction of the field line at a point is the direction in which a small mass would move when placed at that point.
What is gravitational field strength?
The force acting per unit mass at any point in a gravitational field.
What does Newton’s law of gravitation state?
The gravitational force of attraction between two point masses is directly proportional to the product of their masses and inversely proportional to the square of their separation.
What do Kepler’s three laws of planetary motion state?
1) Planets travel around the sun in elliptical .
2) A line joining the sun to a planet will sweep out equal areas in equal times
3) The time period of the orbit squared is is proportional to the mean radius of the orbit cubed.
What is a geostationary orbit?
An orbit of the earth made by a satellite that has the same time period and orbital direction as the rotation pf the earth and in the equatorial plane.
What are geostationary satellites used for?
- Broadcasting TV signals and relaying mobile phone signals
- Monitoring the weather and changes to the environment
- Monitoring air traffic
What is the gravitational potential at a point in a gravitational field?
The work done in moving a unit mass from infinity to that point.
What is escape velocity?
The velocity an object would need to travel to escape a gravitational field.
