Study of the spring lunching system of pinball

[please help i]

A ball of the pinball of mass 0.1kg assimilated to a point M is launched by a spring and move up without friction in a track straight 60m (the sprin is in the track) then move curvely to an arc of a half circle with radius 20m at the topof the track.
The plan contain the track and the arc is made a angle of 10 degree to the horizontal.
the initial length of the spring is 12cm. the end of the spring is fixed to the initial position of the track and the ball is put on the other end of the spring. It compressed until its length become x. It launched with initial velocity 0m/s. the spring constant is 40N/m
1) what is position of the ball during lunching lost contact with the spring? and it velocity.
2) using the mecanical energy theorem, express the position of the ball stop in the track in function of x.
3) plot the curve of X = f(x) how much the compess length minimum need so that the ball leach the end of the half circle arc of the track?

 

[please help i]

1) i know that the legth compressed is L-(L-x), thus the length extend will be the same so if there is no frictional force inside the then i know that the ball lost contact with the spring is L+(L-x)...but how to prove??