1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: A GM1m2/r2 question

  1. Oct 11, 2005 #1
    Pelle who weights 68 kilos, cycles up a steep hill. He stands up and pushes all his weight on the pedals. Pedals moves in a circle with the radie 18cm. Which is the biggest momentum he can affect the pedals with

    Well my answer is wrong but this is how I did
    Because I don't know the answer I take

    m2= 9,82*(0,18)^2 = 0,318168/6,67*10^-11 = 4770134933
    Which is the second mass

    M1 = His weight 68kg

    Then I take 68*4770134933 =3,24691754^10*-11 * 6,67*10^11 = 21,635424
    and then I finely dived it which is 21,635424/0,18^2 = 667,76 N

    I get but it's not right answer should be 120Nm please help me !:surprised :surprised :surprised :surprised :surprised
  2. jcsd
  3. Oct 11, 2005 #2


    User Avatar
    Homework Helper

    The unit of moment of a force (often called torque) is Nm, and the equation:
    [tex]\mathbf{M} = \mathbf{r} \times \mathbf{F}[/tex]

    This problem has little to do with gravitation.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook