where / is the coefficient of friction, p is the weight of the ice related to a unit of surface, and F is 

 the weight of the load which started the given piece into motion (through a system of pulleys). 



As a result of 325 tests of Neva River ice (4 samples of ice) and Baltic Sea ice (5 samples) and 

 375 tests of Kara Sea ice (8 samples), Arnold-Aliabev obtained the results compiled in table 65. 



TABLE 65. THE COEFFICIENT OF EXTERNAL FRICTION OF WET ICE 



The columns in the table deal with the following: A with an unpainted surface and B with a 

 surface painted with red lead. The experiments were conducted under a positive air temperature 

 and therefore the friction was moist. 



The results presented in table 66 deal with experiments conducted with ice of the Baltic Sea 

 and unpainted steel at a temperature of -5.3°; therefore, these are the coefficients for the case of 

 dry friction. 



TABLE 66. THE COEFFICIENT OF EXTERNAL FRICTION OF DRY ICE 



Arnold-Aliabev notes that in moist friction, the friction coefficient at rest is 1. 5 times 

 greater than the friction coefficient in motion, but in dry friction the ratio of these amounts reaches 

 10. The coefficients of moist friction for ice of various origins hardly differed from each other. 

 Figure 68 shows the relationship of the frictional coefficient to the amount of load expressed in 

 grams per square centimeter. Arnold-Aliabev points out that the curves of the same form are ob- 

 tained for both painted and clean steel and are inherent to various ice types. 



OJl 



lu O 



1^ S= OA 



O 

 U 



0.10 



LOAD IN G/CM'^ 



Figure 68. Curve of ice-steel friction under different loads. 



201 



