Gravitational Field

Question 1

Define Gravitational Field/ gravitational field strength.

Answer 1

Force per unit mass

Question 2

What are the three conditions for the orbit of a satellite to be geostationary?

Answer 2

-Period = 24h
-The orbit has to be equatorial
-The orbit has to be from West to East.

Question 3

What is Newton’s Law of Gravitation?

Answer 3

Gravitational force is directly proportional to the product of the masses. The force between the masses is inversely proportional to the square of their seperation.

Question 4

Define Gravitational Potential at a point

Answer 4

It is the work done per unit mass in bringing a mass from infinity to the point.

Question 5

Why is gravitational Potential negative?

Answer 5

-At infinity the gravitational potantial is equal to zero.
-Gravitational force is attractive so work gets done as the object moves from infinity so potential is negative.

Question 6

What are three simlarities between gravitational and electrical potential?

Answer 6

-They are bot inversely proportional to the separation.
-They are both zero at infinite distance.
-Points of equal potential lie on concentric spheres.

Question 7

What is indicated by the direction of the gravitational field line at a point in a gravtational field?

Answer 7

Direction of the force acting on the mass placed at the point

Question 8

Explain with reference to gravitational field lines why the gravitational field near the surface of the Earth is approximately constant for small changes in height.

Answer 8

-Change in height negligible compared with radius of Earth.
-Gravitational field lines practically parallel.