1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

If the mass of the planet is 1.38 x 10^25 kg and its radius is 4.30 x 10^7 m

  1. Nov 23, 2012 #1
    If the mass of the planet is 1.38 x 10^25 kg and its radius is 4.30 x 10^7 m....

    1. The problem statement, all variables and given/known data

    {attachment}

    (all the formulas in the attachment too)

    I don't know how to start this question Please help -[
     

    Attached Files:

  2. jcsd
  3. Nov 23, 2012 #2
    Re: If the mass of the planet is 1.38 x 10^25 kg and its radius is 4.30 x 10^7 m....

    I think that you are thinking about this too hard.

    [itex]F_{gravity} = G\frac{m_{1}m_{2}}{r^{2}}[/itex]

    You know G, which is a constant. You know the two masses (the planet and the apple). You know the radius of the planet. Find the force. Then, it's a simple question of [itex]\sum{\vec{F}} = m\vec{a}[/itex].
     
  4. Nov 23, 2012 #3
    Re: If the mass of the planet is 1.38 x 10^25 kg and its radius is 4.30 x 10^7 m....

    Oh I think i overlooked the F=Gm1m2/r^2 formula and wasn't able to work with the other formulas that were provided. Thanks for the help! =))
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook