CH3 Flashcards
Newton’s universal law
of gravitation
The gravitational foce between two bodies is directly proportional to the
product of the masses of both bodies and inversely proportional to the
square of the distance between the centres of the two bodie
Centripetal force
A force acting on a body in a circular motion in a direction towards the centre of the circle
Why is Gravitational Force Universal?
It acts between any two bodies in the universe
Relationship of Gravitational Force/Acceleration, g/G with mass of the earth when distance,r < radius of earth
g/G is directly proportional to r
Relationship of Gravitational Force/Acceleration g/G with mass of the earth when distance,r < radius of earth
g/G is directly proportional to r
2 Data needed to calculate mass of a planet / sun
Period of revolution
Radius Of Orbits
Kepler’s first law
-Law of Orbit
-All planets move in an elliptical orbit with sun at one FOCUS
Kepler’s second law
A line that connects a planet to the Sun sweeps out equal areas in
equal times (Law of Areas)
Kepler’s third law
The square of the orbital period of any planet is directly proportional to cube of radius of the orbit of the planet (Law of Periods)
Definition of Orbital radius
Average value of distance between a planet and the sun
Orbital period of Geostationary Satellite
24hours
Orbital period of Non-Geostationary Satellite
<24 hours<
Direction of motion of Geostationary Satellite
Same as direction of earth rotation
Direction of motion of Non-Geostationary Satellite
Need not be the same as direction of earth rotation
Purpose of Geostationary Satellite
Communication
