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

Calculating Earth Force

  1. Jun 29, 2005 #1

    If at a particular time, I have the r distance from the Sun to Earth, the value of the velocity of Earth, and the angle between the velocity vector and the r vector, how can I calculate the force that Earth has regarding the tangent? Suppose I wanted to go againts the movement of the Earth. Which force should I go against and how do I calculate it?

    Kind regards,

  2. jcsd
  3. Jun 29, 2005 #2
    In a direction tangential to its orbit , earth has an obital velocity vector prependicular to the vector 'r' . This velocity vector can be calculated easily.

    Considering the system to be considering only of Sun and Earth , therefore , Sun's gravitational pull provides the necessary centripedal force :


    \frac {GMm}{r^2} = \frac {mv^2}{r}

    Calculate the velocity from here . This the velocity you have to counteract by going against the motion of earth. To bring earth to rest , you can calculate the work needed by the work-energy principle.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook