Accelerate to a angle

So guys, i’m having a hard time to figure this out, so any help will be much appreciated.

The situation is the following, i want to spawn a ball object that accelerates toward a direction, and the strength (speed), of acceleration is based on how far has the user dragged the touch, that is basically, this

if(event.phase == "ended") then             strengh = event.x - event.xStart              destination = event.y end  

I tried a couple of functions like object:applyForce, and object:setLinearVelocity()

but i really not sure how to make this work.