164 LABORATORY LESSONS IN GENERAL SCIENCE 



1. Make two freehand drawings on your paper similar 

 to the cut, showing in the first one movable pulley in use, 

 and in the second two movable pulleys. In all cases repre- 

 sent one end of the cord attached to the fixed pulley. 



FIG. 73. Diagram of pulleys. 



2. Let the teacher fit up pulleys in turn representing 

 these same conditions, and determine by use of the spring 

 balance in each case (a) the value of the resistance overcome 

 (i.e., the weight of movable pulley and its attached body J ) ; 



1 Any friction, or resistance other than gravity, is disregarded here. 



