How do you beat level 15 on construction fall cool maths games

First take the super ball hit it at the edge of the silver thing as hard as you can. then take the black ball on the hill and hit the wheel in front of it as hard as you can. then right when you do that take the ball in front of all of them then shoot it at the building thingy and you got it (if you don't, restart it and do it again)