The moon takes about `27.3` days to revolve around the earth in a nearly circular orbit of radius `3.84xx10^5 km`. Calculate the mass of the earth from these data.

Calculate the value of g in the following two cases: (a) If a mango of mass 1/2 kg falls from a tree from a height of 15 metres, what is the acceleration due to gravity when it beigns to fall? (b) Consider a satellite orbiting the Earth in a circular orbit of radius 1600 km above the surface of the Earth. What is the acceleration experienced by the satellite due to Earth's gravitational force?

A satellite is to revolve around the Earth in a circle of radius 8000 km. The speed at which this satellite be projected into an orbit, will be:

Two satellite A and B of the same mass are revolving around the Earth in circular orbits such that the distance of B from the centre of the Earth is thrice as compared to the distance of A from the centre. What will be the ratio of centripetal force on B to that on A.

The planet Mars has two moons, phobos and delmos. (i) phobos has a period 7 hours, 39 minutes and an orbital radius of 9.4 xx 103 km. Calculate the mass of mars. (ii) Assume that earth and mars move in circular orbits around the sun, with the martian orbit being 1.52 times the orbital radius of the earth. What is the length of the martian year in days ?

A mars satellite moving in an orbit of radius 9.4xx10^3 km take 27540 s to complete one revolution. Calculate the mass of mars.

An electron of mass 9 xx 10^(-31) kg revolves around a nucleus in a circular orbit of radius 0.53 Å . What is the angular momentum of the electron? (Velocity of electron is, v=2.2 xx 10^(6) ms^(-1)).

An electron moving with velocity 2.2 xx 10^(6) m/s, revolving in circular orbit of radius 0.53 Å. Calculate its angular velocity.