Calculate the orbit velocity

  • I have got the physics part down to make a satellite use physics to orbit around a planet. I used a formula given by leparlon:

    -Set the world gravity to 0

    -Physics behaviour in all the objects in with the gravity force will act (in this case, the crates).


         Each 0.5 seconds (for better performance)

         Apply Force On CRATE Toward position MOON.X, MOON.Y->GLOBAL_VARIABLE * (CRATE.mass + MOON.mass) / ((CRATE.X - MOON.X)*(CRATE.X - MOON.X) + (CRATE.Y - MOON.Y)*(CRATE.Y - MOON.Y))

    My Question: Using a variable "mass" on the planet and object, and using the distance between the moon and object, how do I get Velocity?

    V=SQRT((G{Gravity}*M{Mass of Moon})/R{Distance of center of moon to object})

    Hint (WHAT IS Gravity in this case???????) You cant use 6.67*10^11...

    Ultimately I want to have the object start out at a perfect speed to create a perfect orbit at start of layout. Distance will vary, as will mass of each moon and object.

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  • I think I will re-ask this question because it was confusing...

    I would like to calculate the velocity it takes a moon to orbit a planet at the start of layout using the following:

    Mass of the objects: I have redone the orbit events to use the moon.physics.mass and planet.physics.mass. FYI-This internal value is calculated using the area of the collision mask (set to circle) * Density (internal physics variable) which can be changed to make an object heavier.

    Distance between the objects: Using Construct 2�s Distance formula. Distance(moon.x,moon.y,Planet.x,planet.y)

    Gravity: This is an unknown to me, and part of my problem.

    According to physics laws, to calculate the velocity of an orbiting satellite, you must use this formula: Velocity= Square root of ((Gravity * Mass of Planet) / Distance between center of planet and Satellite center). I need to know what I use for Gravity�

    Currently I have an initial impulse hard set as a onetime event that sends the satellite moon into orbit, but it took many tries to figure out an optimal number.

    Here is the Link to my Example:

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