THE INFLUENCE OF DISTURBING ACCELERATI ONS 125 



of the disturbing acceleration from the oscillatory amphtude of the gravi- 

 meter pendulum. 



In order to be able to calculate the dynamic coefficient one needs to know 

 the damping coefficient e in addition to the natural frequency of the disturb- 

 ing oscillations. 



Let us examine equation (2) to find the value of s. 



Equation (2) indicates that when the gravimeter pendulum is deflected 

 by an angle 6q it \vi\l return to a position of equihbrium exponentially. 



Let us find approximate values for a^ and ao ; 



Substituting in equation (2), we obtain 



-Lilt I 9 2 - /^Of_^'^/\ 



e.-^oe ^- (l-g-g,a ^--■^). (4) 



^2 -(■u--!i)l ... 

 The term — -^ e * is vanishingly small, since in the marine 



gravimeter the value of e must be greater than 1000 and the value tIq not 

 greater than 10: 



Let us write the expression (5) for two moments of time and take their ratio. 



QT-, = e - ^ . (6) 



Converting into logarithms we obtain 



Let us rewrite formula (6), replacing 0<^ in it by A^—Aq, and 0o" by 

 A^—Aq, where Aq is the reading on the gravimeter scale when the bar 

 is in a position of equilibrium, Aj^ and A2 are the readings for moments of 

 time ti and t^. 



rl..z^.,-H' "-'.', (8) 



whence 



where B = e 2 



_A^Bei^^)-A, 



