an a astronaut stands on the surface of a spherical asteroid that has a weak gravitational field but no atmosphere

Explain in physical terms how a microwave oven works. what would happen when you put a conductor in the microwave oven? explain.

Which is an example of an exothermic process?

Two identical stars with mass m orbit around their center of mass. each orbit is circular and has radius r, so that the two stars are always on opposite sides of the circle. (a) find the gravitational force of one star on the other. (b) find the orbital speed of each star and the period of the orbit. (c) how much energy would be required to separate the two stars to infinity?