Possibilities

One possibility is

Spoiler

not using the balls at all.

The level has many ways to win - stopped at 2. Thanks

@Don G Rowe | @gmacpro
Thanks for playing and for comments and ratings
This level doesn't limit its players' problem-solving process to determined constraints, that's why the level is called "Possibilities."

come out and win..

@aa kim
an easy win indeed

Spoiler

I've counted 9 possibilities so far, and one of it, as mentioned by @Don G Rowe, is not using any balls at all, which requires at least three tricks.
Coming out is the obvious way, but it's just one of the solutions. There are three balls.

Spoiler: My Solutions:

1: Hit one ball with the slider against the slope into the floating winning block. (Trial and error)
2: Hit B repetitively with the slider—avoiding the slope—until it hits the winning block. (Trial and error)
3: Fill empty blocks with the balls. Slightly move the first ball, then hit the second with the slider—gentle force required—against the wedge into the other ball.
Rotate the draggable attached to the motor and wait for R to come across then ditch him off. Now it's safe for B to traverse to the draggable which leads to the winning block near the zapper.

@aa kim |
the level's descriptions says that it should be played with the balls,
and that's the only constraint that prevents us from using the tricks we've known

Good fun exploring solutions