346 Mr Vincent, Experiments on Impact. 



The diameters of the balls were 1-27, 2*54 and 3*81 cms. 

 respectively. The block measured 8*5 x 8 - 5 x 13'5 c.cms. 



In this figure the ordinates as before are proportional to the 

 square of the diameter of the dent, while the abscissa? are pro- 

 portional to the velocity of approach, the numbers being the roots 

 of the heights of fall. 



Reading the straight lines we have, when h = 100 cms., 



d 2 =l'22, -52, -12, 



or d =111, -72, -35, 



so that the diameter of the dent is approximately proportional to 

 the diameter of the ball which makes it, other things being the 

 same. 



AT WMDu 2 8p /DhiV 

 JN ow v = r. — or -4r — rr 



p 



7T< 



d 4 3 U 2 



where p = the density of the steel. 



Thus the above results agree with the law that p is constant. 

 Adapting the above equation for direct computation from the 

 figure, we have 



_ 16 pg / D 2 \/h 

 P ~~ 3 V # 



= a/3 2 ; 



p for the steel balls was determined and was found to be 7*78 

 grammes per c.cm. ; a is thus 4"07 x 10 4 . 



The values of j3 for the three balls are set out below : 



The value of ft decreases in the above table, while D increases. 

 This is due to some fortuitous circumstance and as will be shown 

 below the linear dimensions of the dent vary with those of the 

 ball very accurately, even when the range of diameter of the ball 

 is greater than in Fig. 10. 



Taking the mean value of /3 we get, for this slowly evolved 

 block, 



p = 6'4 x 10 8 dynes per sq. cm. 



Again, the specimen of lead has a small value for p, and the 

 curves in this figure bend over towards axis of velocities. 



