Find the mass of earth (Given the radius of earth `R= 6.4 xx 10^6 m)`.

Calculate the mass of the earth. Given radius of the earth =6.4xx10^-6 m and g = 9.8 m//s^2

The earth’s surface has a negative surface charge density of 10^-9 C m^-2 . The potential difference of 400 kV between the top of the atmosphere and the surface results (due to the low conductivity of the lower atmosphere) in a current of only 1800 A over the entire globe. If there were no mechanism of sustaining atmospheric electric field, how much time (roughly) would be required to neutralise the earth’s surface? (This never happens in practice because there is a mechanism to replenish electric charges, namely the continual thunderstorms and lightning in different parts of the globe). (Radius of earth = 6.37 xx 10^6 m .)

A satellite is launched into a circular orbit 1600 km above the surface of the earth. Find the period of revolution, the radius of the earth R = 6400 km and the acceleration due to gravity is 9.8 m//sec^2 .

A T.V. tower has a height of 125 m. What is the maximum distance and area upto which this T.V. trasmission can be received? (Given: Radius of earth = 6.64 xx 10^(6)m )

If mass of Earth is 6xx10^24 kg, radius of Earth is 6.4 xx 10^6m and the gravitational constant is 6.7 xx10^-(11)Nm^2kg(-2) . Calculate the value of g.

A satellite orbits the earth at a height of 400 km above the surface. How much energy must be expended to rocket the satellite out of the earth’s gravitational influence? Mass of the satellite = 200 kg, mass of the earth = 6.0xxl0^24 kg , radius of the earth = 6.4 xx 10^6 m , G = 6.67 xx 10^11 N m^2kg^2 .

A transmitting antenna at the top of a tower has a height 16m and the height of receiving antenna is 25m.What is the maximum distance between them for satisfactory communication in LOS mode? Given radius of earth is 6.4 xx10^6 m .