931 
From Fig- I-9: 
MPa = mx, + Kil(x, - x,) (I-53) 
Fron Fig. I-10: 
and 
mPA = mon - \m(x, - x,) (1-54) 
By definition: 
and (I-55) 
Combining Eqs- (I-55) and (I-54), substituting Eq. (I-55), and assuming P 
to be a function of time: 
mM eo Ma - mA 
+ P(t) (1-56) 
Equation (I-56) may be written: 
px+kx = 6 P(t) (I-57) 
where: 
—_ mM 
be ace (equivalent mass) (I-58) 
6 = = = a (equivalent area) (I-59) 
4s M— > © (rigid mounting), 
nn end Bier (1-60) 
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