G-Force

Question 1

Why is gravitational potential negative?

Answer 1

• Gravitational potential at infinity is taken to be 0
• Since gravitational force is attractive in nature, force exerted by external agent is acting opposite direction to the displacement of a small test mass.

Question 2

Define Newton’s Law of Gravitation

Answer 2

It states that 2 point masses attract each other with a force that is proportional to the product of their masses and inversely proportional to the square of the separation between them.

Question 3

Define gravitational field

Answer 3

It is a region of space in which a mass experiences a gravitational force.

Question 4

Define gravitational field strength

Answer 4

Grav field strength at a point in a gravitational field is defined as the gravitational force per unit mass acting on a small test mass placed at that point.

Question 5

Define gravitational potential energy

Answer 5

GPE 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.

Question 6

Define gravitational potential

Answer 6

GP at a point in a gravitational field is defined as the work done per unit mass by an external agent in bringing a small test mass from infinity to that point.

Question 7

Advantages of a geostationary satellite

Answer 7

• there is continuous surveillance over the region under it
• it is easy for ground station to communicate with it as it is permanently within view.
• due to high altitudes, satellites can transmit and receive signals over a large area.

Question 8

Disadvantages of geostationary satellites

Answer 8

• significant loss in signal strengths
• poorer resolution in imaging satellites
• time lag in telecommunications