Q Topic: Using Dr. Weil's Math Shortcut on Gravity and Light Purpose This activity assesses students' ability to apply this learning objective: Use Dr. Weil's Math Shortcut to solve problems in astronomy. Review the video again if it will help. And here is the pdf file. Beginning Dr Weil's Shortcut 21.pdf Download Beginning Dr Weil's Shortcut 21.pdf The two sentences you need to remember are: Both on top, do the same thing. One on top and one on bottom, do the opposite. Only a student's first post can be counted because everyone else's posts are visible after you post the first time. I will grade and discuss your answers after the discussion period has closed. Directions The Canvas Student GuideLinks to an external site. provides instructions for replying to a discussion postLinks to an external site.. Part 1: Due Thursday at 9pm. 1. Suppose there are two galaxies orbiting one another. The force between them can be calculated using Newton’s Law of Universal Gravitation. (I recommend writing down the equation and using our shortcut to complete these questions! Then post the answer you believe is correct in this form: Weaker. Two times weaker.) a) Imagine that the mass of one of the galaxies magically becomes twenty times bigger. Would the gravitational force between them become stronger or weaker? How many times stronger or weaker? b) Imagine instead that the distance between the two galaxies becomes two times smaller. Would the gravitational force between them become stronger or weaker? How many times stronger or weaker? c) Suppose one galaxy’s mass became nine times smaller. Would the gravitational force between them become stronger or weaker? How many times stronger or weaker? 2. Understanding photons of light! An X-ray photon has a wavelength of 10 nanometers (nm) and an ultraviolet photon has a wavelength of 100 nm. a) Using the equation that relates wavelength and frequency. Which photon has the smallest frequency? How many times smaller? b) Using the equation that relates wavelength and energy. Which photon has the biggest energy? How many times bigger? c) Which if either photon moves faster through a vacuum? Why? 3. Two objects each produce a continuous spectrum. Object 1 has a peak wavelength of ?1 = 1600 nm. Object 2 has a peak wavelength of ?2 = 200 nm. a) Using Wien’s Law. Which object is hotter? How many times hotter is it than the other? b) Which object looks redder?