Make an object revolve around another object

Questions
1

I’m trying to make an object revolve around another. I thought it could be done using applyForce, but the object either doesn’t move much at all, or it revolves and slows down. Is there a way to make it revolve at a certain speed? Here is the code for it.


-- revolution example test

-- Use this function to perform your initial setup
function setup()
    --creating the object that will be revolved around
    center = physics.body(CIRCLE, 40)  
        center.x = WIDTH/2
        center.y = HEIGHT/2
        center.type = STATIC

    --creating the revolving object
    asteroid = physics.body(CIRCLE, 40)  
        asteroid.x = 400
        asteroid.y = 200
        force = vec2(math.cos(asteroid.x),math.sin(asteroid.y))   
        asteroid:applyForce(force * 100) -- apply force from center of mass          
        
        joint = physics.joint(REVOLUTE,center,asteroid,vec2(center.x, center.y))
    
end

-- This function gets called once every frame
function draw()
    -- This sets a dark background color 
    background(40, 40, 50)
    
    -- This sets the line thickness
    strokeWidth(5)

    -- Do your drawing here
    ellipse(center.x,center.y, 40)
    sprite("Space Art:Asteroid Small", asteroid.x, asteroid.y)
    
end
2

.@evanlws12 I added displayMode(FULLSCREEN), asteroid.gravityScale=0, and changed the force*2000. Also see http://twolivesleft.com/Codea/Talk/discussion/comment/17036#Comment_17036


displayMode(FULLSCREEN)

-- revolution example test

-- Use this function to perform your initial setup
function setup()
    --creating the object that will be revolved around
    center = physics.body(CIRCLE, 40)  
        center.x = WIDTH/2
        center.y = HEIGHT/2
        center.type = STATIC

    --creating the revolving object
    asteroid = physics.body(CIRCLE, 40)  
        asteroid.x = 400
        asteroid.y = 200
        force = vec2(math.cos(asteroid.x),math.sin(asteroid.y))   
        asteroid:applyForce(force * 2000) -- apply force from center of mass          

        joint = physics.joint(REVOLUTE,center,asteroid,vec2(center.x, center.y))
        asteroid.gravityScale=0

end

-- This function gets called once every frame
function draw()
    -- This sets a dark background color 
    background(40, 40, 50)

    -- This sets the line thickness
    strokeWidth(5)

    -- Do your drawing here
    ellipse(center.x,center.y, 40)
    sprite("Space Art:Asteroid Small", asteroid.x, asteroid.y)

end