Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Two gravitation questions

  1. Apr 16, 2008 #1
    1) In 2004 astronomers reported the discovery of a large Jupiter-sized planet orbiting very close to the star HD 179949 (hence the term "hot Jupiter"). The orbit was just 1/9 the distance of Mercury from our sun, and it takes the planet only 3.09 days to make one orbit (assumed to be circular). What is the mass of the star? Express your answer (a)in kilograms and (b)as a multiple of our sun's mass.
    How fast (in km/s) is this planet moving?

    2) The International Space Station makes 15.65 revolutions per day in its orbit around the earth. Assuming a circular orbit, how high is this satellite above the surface of the earth?
  2. jcsd
  3. Apr 16, 2008 #2
    Please show some attempt at the solution. Once we see we're your trouble is, we'd be glad to help you.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook