[ODE] how to setup this scenario?

[Javier Loureiro Varela]

        I'm doing small pinball game using ODE...

        To send the ball onto the playfield, I have a small stick
        with a strong spring. When I hit space, the stick receives a
        force backwards that alongs the spring. When I release the
        key, it kicks the ball with more or less energy. I guess
        everybody is able to understand my explanation...

        How is the best way to do this with ODE?

        any idea will be aprecciated...

--
Signed,

  Javier Loureiro Varela