Which of the following astronomer first proposed that sun is static and earth rounds sun
Copernicus
Kepler
Galileo
None
The time period of a geostationary satellite is $24\; \mathrm{h}$, at a helght $6 \mathrm{R}_{\mathrm{E}}( \mathrm{R}_{\mathrm{E}}$ is radius of earth) from surface of earth. The time period of another satellite whose helght is $2.5 \mathrm{R}_{\mathrm{E}}$ from surface will be
According to Kepler, the period of revolution of a planet $(T)$ and its mean distance from the sun $(r)$ are related by the equation
Explain Kepler’s first (Law of Orbits) law for planetary motion.
The orbital speed of Jupiter is
A satellite revolving around a planet in stationary orbit has time period 6 hours. The mass of planet is one-fourth the mass of earth. The radius orbit of planet is : (Given $=$ Radius of geo-stationary orbit for earth is $4.2 \times 10^4 \mathrm{~km}$ )