Due Date: Apr. 14, 2008
Instructions: Print and complete the following homework assignment. Make sure you write your name on the paper.
Name: ________________________________________
Warnings:
1) There will be less partial credit given for incorrect solutions for this homework assignment than was given for previous assignments.
2) If you do not show how you got your answer then you will not get credit for that problem.
Calculate (attach a separate sheet for the answers in this section) each of the following. Show all of your work. Note that you must explicitly write the correct units for each problem. (10 pts each, i.e. there is a total of 50 points).
Assuming that there is a 4 million solar mass black hole at the galactic center, what will the orbital period be for a high-mass star orbiting the galactic center at an average distance of 1 ly?
a) A 10 N force acts on a 10 kg object. What will the acceleration of the object be?
b) A 10 N force acts on a 10 g object. What will the acceleration of the object be? (Note that it would be nonsensical to get the same answer for both parts of this problem).
a) How much energy does the Sun produce in 1 minute?
b) How much mass does the Sun convert to energy every minute?
a) What is the surface area of the Sun?
b) What is the flux (recall that flux is power per unit area) at the Sun's surface?
c) Based on your answer in part b, what is the temperature at the Sun's surface?
a) The burner on a stove is glowing a dull red. The black body spectrum of the burner indicates that it is emitting a greater intensity of 1 mm light than any other wavelength. What is the temperature of the burner?
b) If the surface area of the burner is 50 cm2, what amount of power is the burner emitting as thermal radiation? (express your answer using the correct standard unit for power).
c) Suppose that the black body spectrum of a white dwarf has a peak intensity for 1 nm light. What is the surface temperature of the white dwarf?