# physics

posted by
**gobind**
.

An asteroid, whose mass is 2.0 10-4 times the mass of Earth, revolves in a circular orbit around the Sun at a distance that is 2.9 times Earth's distance from the Sun.

(a) Calculate the period of revolution of the asteroid in years.

(b) What is the ratio of the kinetic energy of the asteroid to the kinetic energy of Earth (Kasteroid / KEarth)?

I repeat: Is there not a Kepler law that relates radius of orbit to period?

since T^2 is proportional to r^3, (a) should be sqrt(2.9^3)years.

(b) find velocity of both the earth (make radius of earth =1r and radius of asteroid=2.9r)the r's will cancel out