Level 19 is not that hard, I would first make a rectangle to connect the "U" with the gap in the oblique line. Then simply push the ball until you can make it go through the gap. Below you have an not so elegant video solutions, check it out if you can't do it using my instructions.
Physics Drop Level 19 Walkthrough, Solution, Cheats for Android, iPhone, iPad, iPod. Note: This is "Physics Drop" by "IDC Games"