Pressure 
Fige 1 - Surface showing variation of pressure with time and 
distance 
Cn eens) reat cs” Vacs wen) yealleead) cae (3) 
If times and distances are now related by 
Gey eds a 560+ MO0G4 8,068) —66d!\ Gag © vodcursided (4) 
Then from equations 2, 3, and 4 
Py oe, Fe. ood cod AGO ~ 606. odG ~Gda § dad (5) 
If two points of given r,.and r, are considered, then for varying t, and t,, 
equations 2 and 3 give the two pressure/time curves at these points. For 
any spherical sound pulse let these pressure/time curves be represented by 
ABC and A'B'C' in fig. 2. These curves are drawn of arbitrary shape. 
