5.4: Gravitational fields

Question 1

Escape velocity

Answer 1

The minimum velocity required by an object to be able to escape a gravitational field of a mass when projected vertically from its surface.

Question 2

Field lines

Answer 2

A line representing the path that a mass would take when placed within the field.

Question 3

Geostationary Satellite

Answer 3

A satellite that orbits above the equator with a 24 hour period, so it will always remain above the same position of the Earth. They orbit approximately 36,000km above the surface of the Earth.

Question 4

Gravitational field strength

Answer 4

The force per unit mass exerted on a small test mass placed within the field

Question 5

Gravitational field

Answer 5

A region surrounding a mass in which any other object with mass will experience an attractive force.

Question 6

Gravitational potential energy

Answer 6

The component of an object’s energy due to its position in a gravitational field.

Question 7

Gravitational potential

Answer 7

The work done per unit mass required to move a small test mass from infinity to that point.

Question 8

Kepler’s first law

Answer 8

All planets travel in elliptical orbits, centred around the sun.

Question 9

Kepler’s second law

Answer 9

All planets sweep out the same area in a given period of time.

Question 10

Kepler’s third law

Answer 10

The square of a planet’s period is directly proportional to the cube of its mean distance to the sun.

Question 11

Newton’s law of gravitation

Answer 11

The force between two masses is proportional to the product of the masses involved and inversely proportional to the square of the separation of the masses