How are the fission and great-impact hypotheses of lunar formation sir
both hypotheses involve the early earth losing material,
both hypotheses are widely accepted.
both hypotheses involve the collision with foreign bodies.
both hypotheses explain why earth is denser than the moon.

Ammonia enters the expansion valve of a refrigeration system at a pressure of 10 bar and a temperature of 18oc and exits at 6.0 bar. the refrigerant undergoes a throttling process. determine the temperature, in oc, and the quality of the refrigerant at the exit of the expansion valve.

Light from a sodium lamp passes through a diffraction grating that has 1000 slits per millimeter. the interference pattern is viewed on a screen 1.000 m behind the grating. the first (m = 1) two bright yellow fringes that are visible are 0.7288 m and 0.7300 m from the central maximum. what are the wavelengths of these two fringes?

Suppose a comet has an orbital period of 309.1 years around the sun. what is it’s average distance from the sun?