Question

An artificial satellite is revolving close to earth. Its orbital velocity mainly depends upon

• A. the mass of earth.
• B. the radius of earth.
• C. the orbital radius.
• D. the mass of satellite.

Answer 1

Answer: (B)

the radius of earth.

For satellite near earth's surface to move in orbit Gravitational Acceleration must be equal to Centripetal Acceleration (they are in opposite directions)
$\frac{V^2}{R}=\frac{GM}{R^2}=\frac{G4\pi R^3\rho }{{3R}^2}=\frac{4\pi }{3}GR\rho$
$\therefore V=\sqrt{\frac{4\pi }{3}G{R}^2\rho }=R\times constant$
As density and G are constants so velocity depends on R. (Not on mass of earth as we can see R was also there in that equation)