Gravitational Fields Flashcards
A satellite in geostationary orbit appears to remain above the same point on the Earth
and has a period of 24 hours.
State two other features of a geostationary orbit.
Ref: 9702/41/O/N/16
equatorial orbit/orbits (directly) above the equator B1
from west to east
What is meant by a field of force?
it is the region of space where a certain particle may experience a force/ the force acts on the particle.
What is gravitational potential at a certain point?
It is the work done per unit mass in bringing a small test mass from infinity to a certain point.
What is the formula for gravitational potential?
phi = GM/R
What is meant by the line of force on a gravitational field?
It is the direction on a small (test) mass or the direction of acceleration on a (small test) mass.
Why is the acceleration of free fall near the earth’s surface approximately constant?
- The lines are radial
- Near the surface, the lines are almost parallel
- Parallel lines have a constant field strength
- constant field strength and hence, constant acceleration of free fall.
State Newton’s law of Gravitation.
The Force between 2 point mass is proportional to the product of the 2 masses and is inversely proportional to the square of their separation.
Explain whether or not planets orbiting in a circular motion around a star are in equilibrium.
No, because there is a resultant force as the velocity is changing.
