82 



THE WHEEL AND AXLE. 



radius of the wheel, which is turned by the hand, to be 

 O m '75. The work required for raising the weight 

 through l m is 50 kilogrammetres ; the same amount 



FIG. 55 (an. proj., -^ real size). 



FIG. 56 (an. proj., real size). 



of work must be done at the circumference of the wheel 

 Now, a point at the circumference of the wheel describe 

 a space of 7 m '5, during the time in which a length c 



