The ratio of escape velocity at earth (v_e) to the escape velocity at a planet (v_p) whose radius and mean density are twice as that of earth is

A satellite S is moving in an elliptical orbit around the earth. The mass of the satellite is very small compared to the mass of the earth. Then,

A remote-sensing satellite of earth revolves in a circular orbit at a height of 0.25 $$ \times $$ 10⁶ m above the surface of earth. If earth's radius is 6.38 $$ \times $$ 10⁶ m and g = 9.8 ms^$$-$$2, then the orbital speed of the satellite is

Kepler's third law states that square of period of revoluation (T) of a planet around the sun, is proportional to third power of average distance r between sun and planet i.e. T² = Kr³ here K is constant. If the masses of sun and planet are M and m respectively then as per Newton's law of gravitation force of attraction between them is F = $${{GMm} \over {{r^2}}}$$, here G is gravitational constant. The relation between G and K is described as