C.方程s,V小量f=0 P p+V(m)≈P+PV下=0 S,+Vi=0 pp=p0p07→p=p0()=p0(1+s)≈p0(1+y) Vp p=po(+rs V s+V=0→s+avs=0C.方程 s,v 小量,f=0 vt = − p 0 1   0 t t s = t +( v)  t + 0v = 0       st +v = 0  ( ) (1 ) (1 ) 0 0 0 0 0 0 p p p p p s p s         =  = = +  + − − vt = − p 0 1   (1 ) 0 p = p +s  s p vt = −  0 0    s p vt = −  0 0    st +v = 0   0 2 2 stt + a  s = 0 2 0  p a =