simulate throwing objects
EXIT [F1] does nothing
DEL [F2] deletes calculated values and sets alpha, startvelocity, g to default
CALC [F3] calculates sw, sh, th with the given values
SIM [F4] displays a graph with the throw curve
HELP [F5] displays a help page with the content of this README
EXIT [F1] return to main menu
PLAY [F6] simulates a thrown ball