1SS 



IOWA ACADEMY OF SCIENCE 



of W/m, and so he must exert an added force of W/m 2 to over- 

 come this. This added force in turn causes an extra thrust on 

 the platform of W/m 2 , and so he must exert an additional pull 



r 



P 



w 



b a 



Fig. 17. 



of \\ m : . Without going further we see that tlie total force 

 he must exert is represented by the infinite series 

 f= W/m+ W/m, 2 + W/m 3 + W/m' + (3) 



By equating equations (2) and (3), and cancelling the W's, 

 we obtain the following series : 



