India’s first artificial satellite was:
India's first artificial satellite was Aryabhata. Launched by soviet union on 19 April 1975
According to Kepler’s Third Law:
Weight becomes zero in a freefall or when the total force on your body is zero. For example, in a freely falling lift the contact force on your body is zero, so the weighing machine would show zero reading. So you are weightless.
Different planets have different escape velocities because:
The formula for calculating the escape velocity from the surface of a celestial body (e.g. a planet) is:
where G is the universal gravitation constant, M is the planet’s mass and R is its radius. Different planets have different mass and radius - and therefore different escape velocity.
Kepler’s second law states that the straight line joining the planet to the sun sweeps out equal areas in equal time. The statement is equivalent to saying that:
According to the second law the orbital radius and angular velocity of the planet in the elliptical orbit will vary. The planet travels faster when closer to the Sun, then slower when farther from the Sun. Hence we can say that the transverse acceleration is zero while radial and longitudinal accelerations are not zero.
A satellite which appears to be at a fixed position at a definite height to an observer is called:
As the relative velocity of the satellite with respect to the earth is zero, it appears stationary from the Earth surface and therefore it is called is geostationary satellite or geosynchronous satellite.
The squares of the periods of revolution of the planets are proportional to the ___________of their semimajor axis of its orbit.
The Law of Periods: The square of the period of any planet is proportional to the cube of the semimajor axis of its orbit.
Which is untrue about orbital velocity?
1.Orbital velocity of satellite is independent of mass of the satellite
2.It decreases with increase in the radius of the orbit and with increase in the height of the satellite
3.it depends on the mass and radius of the planet about which the satellites revolves.
4.The angular momentum of a satellite of mass m moving with velocity vo in an orbit of radius r=(R+h) is given by L=√GMm2r
A satellite moves in a circular orbit around earth. The radius of this orbit is one half that of moon’s orbit. The satellite completes one revolution in:
The time period of revolution of the moon around the earth = 1 lunar month.
► Ts/Tm = (rs/rm)3/2 = (1/2)3/2
► Ts = (2)-3/2 lunar month
Kepler’s law of areas can be understood as a consequence of:
Conservation of angular momentum:
L= 2m dA/dt