Spring and Mass settings
 ------------------------

  The gadgets  in this group control the  physical attributes  of  the
selected  masses and springs. Additionally, when  a new mass or spring
is created, it will be initialized with these values.


Mass, Elas

  The "mass"  and "elasticity" of  a mass  can be changed by selecting
the mass  and changing the values on these  gadgets (see  Masses).


Kspr, Kdmp

  To change the "Kspring" or "Kdamp" of a spring, change the values of
the gadgets when the spring  is  selected  (see   Springs ).


Fixed Mass

   To make a mass fixed or unfixed, check or uncheck this checkbox
while the mass is selected (see  Masses).