336 Mr Vincent, Experiments on Impact. 



This curve shows that e (as thus computed, without allowing for 

 air effects) is a linear function of the velocity, for a long range. 



Using the same notation as before, we have 



e = '72, 

 m = 00016; 

 e is zero when 



u = 4500 cms. a sec. approx. 



The vertex of the parabola 



v = e u — mu? 

 is at the point 



u = ~ = 2250 cms. a sec, 

 Am 



e ^ 

 v = j^- = 810 cms. a sec. approx., 



while the value of e corresponding to this point would be 



| = -36. 



The curves B on Fig. 4 were drawn from results obtained 

 with a " squash rackets " ball. 



e = -69, 

 m = -00018 ; 



e is zero when u = 3800 cms. a sec. approx. The vertex of the 

 parabola v = e u — mu 2 is at the point w=1900 and v = 670 cms. 

 a sec; e is then "35. 



Experiments with a Steel Ball and Indiarubber Bung. 



Fig. 5 shows the results of two series of experiments on the 

 bouncing of a steel ball from a large new rubber bung. The ball 

 was of " hard " steel, brightly polished. It weighed 67 grammes 

 and measured 2'54 cms. in diameter. The bung was of grey 

 rubber 4*9 cms. thick, and its circular ends were 6"5 and 8*2 cms. 

 in diameter respectively. 



The larger of its two plane surfaces was cemented to a large 

 stone block and the impacts were made to occur at the centre of 

 the smaller surface. 



