How can let one object collision with line??
Eg: Have a line which slope is 2 and the object (ball ) sleep is 5 and then fly toward to that line. how can let it reflect when the object (ball) collision with line??
Your talking about programming physics and collision.
Search the web, or buy a book, e.g.
I don't know much about physics, but I am guessing you need to use things like.
Equations of motion.
Line/Sphere intersection equation.
And then work out angle of reflection, and send the object off on the new vector.
Basically you are going to have to learn some maths.
And after that, you will need to learn some more maths