a star has its total mass given by the expression: 3 where pe is a constant equal to the density at the center of the star and r is the radius at the surface of the star. the density of the star depends linearly on radius as follows: a(r) = ar + b where a and b are constants. a. determine the complete expression for ρ(r) by finding a and b. you may assume spherical symmetry b. assuming the star is in hydrostatic equilibrium, find an expression for the internal pressure as a function of radius, p(r). c. find and expression for the gravitational potential energy of this star, ω, as well as its total internal energy, u.

The sun generates both mechanical and electromagnetic waves. which statement about those wave is true?

An incident ray through the focal point of a spherical mirror will: reflect through the center of curvature. reflect back through the focal point. reflect parallel to the principle axis. reflect the same direction as the incident ray.

Imagine you are riding on a yacht in the ocean and traveling at 20 mph. you then hit a golf ball at 100 mph from the deck of the yacht. you see the ball move away from you at 100mph, while a person standing on a near by beach would observe your golf ball traveling at 120 mph (20 mph + 100 mph). now imagine you are aboard the hermes spacecraft traveling at 0.1c (1/10 the speed of light) past mars and shine a laser from the front of the ship. you would see the light traveling at c (the speed of light) away from your ship. according to einstein’s special relativity, how fast will a person on mars observe the light to be traveling? a) 0.1c (1/10 the speed of light) b) c (the speed of light) c)1.1c (c+0.1c)