Conservation of Energy 



59 



shown in Figure 27. The nail is the fulcrum of your lever. 

 Now hang the pail on one of the notches about halfway 

 between the fulcrum and the end of the stick and put your 

 hand on the opposite side of the yardstick at about the same 

 distance as the pail is from the fulcrum. Raise and lower 

 the pail several times by moving the opposite end of the 

 lever up and down. See how much force it takes to move 

 the pail. 



Now slide your hand toward the fulcrum and lower and 

 raise the pail from that position. Is it harder or easier to 

 lift the pail from here than from the first position? Which 

 moves farther up and down, your hand or the pail? 



Next, slide your hand all the way out to the end of the 

 yardstick and raise and lower the pail from there. Is the 

 pail harder or easier to lift? Does the pail move a longer 

 or a shorter distance up and down than your hand? % 



If you wanted to move the pail a long way without moving 

 your hand as far, would you put your hand nearer to the 

 fulcrum or farther from it than the pail is? 



FIG. 27. The yardstick is a lever by which he lifts the pail. 



