The mean radius of earth is `6,371 km` and mass is_____.

The mean radius of sun is_____ and mass is_____.

The mean radius of moon is____ and mass is.

An Airforce plane is ascending vertically at the rate of 100 km/h. If the radius of the Earth is r km, then how fast is the area of the Earth visible from the plane increasing at 3 min after it started ascending ? Given that the visible area A at height h is given by A = 2pi r^(2) (h)/(r + h) .

A man weight 60 kg-wt at the earth's surface The radius of the earth is 6400 km. At what height above the earth's surface, his weight becomes 30 kg wt ?

The mass of proton is_____ and of neutron is_____.