A Cassegrain telescope has a hole in the main mirror. This reduces the mirror area and thus the light gathering power, but how much? Suppose a ten inch diameter mirror has a one inch diameter hole in the center. How much of the light gathering power is lost because of the hole?

At very high pressures, gases become and will eventually a) more dense; become hotter b) more dense; change to a liquid or solid c) less dense; combust d) less dense; turn into a liquid

A250-n box is at rest on a frictionless horizotal floor. then a person shoves the box with a non-zero force of magnitude p. which statement best describes the relationship betweeen p and the motion of the box after it was shoved? -the box will not move when p< 250n but otherwise will accelerate at a constant rate that is directly proportional to p - the box will begin moving at a speed that is directly proportional to p, then will gradually slow to a halt -the box will move with constant velocity at a speed that is directly proportional to p -box will accelerate across the floor at a constant rate that is directly proportional to p

Contains chemical energy. a. heat b. light c. natural gas