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!

Correct Formula?

  1. Oct 5, 2004 #1
    Calculate the effective value of g, the acceleration of gravity, at 3330 m above the Earth's surface.

    Isn't the value of g always -9.8 m/s^2?
     
  2. jcsd
  3. Oct 5, 2004 #2

    robphy

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    g has magnitude 9.8 m/s^2 near the surface of the earth

    Generally, g=GM/R^2 where M=mass of the earth, R=distance from the earth's center, and G is Newton's gravitational constant.
     
  4. Oct 5, 2004 #3
    so if I wanted to Calculate the effective value of g, the acceleration of gravity, at 3330 km above the Earth's surface.

    I would times 6.6742 × 10−11 (G) by earth's mass and then divide it by 3330km^2? How do I know Earth's mass?
     
  5. Oct 5, 2004 #4

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    Write your "effective acceleration of gravity" as a fraction of "ordinary acceleration of gravity" (this bypasses the need to calculate the mass of the Earth and G, but you should know the radius of the Earth.)
    And no, you should NOT divide with 3300 squared. Think again.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?