Jumping on moving platforms - lua

Question

I've just started using Corona SDK, and I'm having some problems applying physics on moving platforms.
Basically I have a platforms moving right to left, and when a object lands on the platform there is no friction, the object fails to move with the platform, so once the platform has moved from underneath the object, the object falls to the bottom of the screen. Has anybody else had this problem? I guess maybe a physics object loses some of its attributes but i don't know which one.
I want that the object can move with the platform, same direction and velocity.
Here's a code sample:
.....
elements = display.newGroup()
elements.anchorChildren = true
elements.anchorX = 0
elements.anchorY = 1
elements.x = 0
elements.y = 0
screenGroup:insert(elements)
player = display.newImageRect("player.png",30,50)
player.anchorX = 50
player.anchorY = 50
player.x = 80
player.y = display.viewableContentHeight - 80
physics.addBody(player, "static", {density=.1, bounce=0.1, friction=1.0})
player:setLinearVelocity( 100, -600 )
screenGroup:insert(player)
.....
....
local gameStarted = false
function jumptoplatform(event)
if event.phase == "began" then
if gameStarted == false then
player.bodyType = "dynamic"
addplatformsTimer = timer.performWithDelay(1000, addplatforms, -1)
moveplatformsTimer = timer.performWithDelay(2, moveplatforms, -1)
gameStarted = true
player:setLinearVelocity( 100, -600 )
else
player:setLinearVelocity( 100, -600 )
end
end
end
function moveplatforms()
for a = elements.numChildren,1,-1 do
if(elements[a].x > -150) then
elements[a].x = elements[a].x - 6
else
elements:remove(elements[a])
end
end
end
function addplatforms()
platform1 = display.newImageRect("platform.png",200,80)
platform1.anchorX = 0
platform1.anchorY = 1
platform1.x = 450
platform1.y = yPosition()
physics.addBody(platform1, "static", {density=1, bounce=0.1, friction=1.0})
elements:insert(platform1)
end
.....
Maybe I have to add an onCollision function, to handle it?, or use joints? Any idea will be appreciated..

Answer 1

When you create a physics body, "static" body type means that bodies does not move under simulation and they behave as if they have infinite mass. Static bodies can be moved manually by the user, but they do not accept the application of velocity. Static bodies collide only with dynamic bodies, not with other static bodies or kinematic bodies.
(More details here: http://docs.coronalabs.com/api/type/Body/bodyType.html)
Try like this:
physics.addBody(player, "dynamic", {density=.1, bounce=0.1, friction=1.0})