NATURE-STUDY 'X.FSSONS. 193 



8. If one weight is three times as heavy as the other, 

 find how their respective distances from the fulcrum 

 compare. 



9. If one weight is five times as heavy as the other, 

 find where the fulcrum must be placed that the weights 

 may balance. 



In these examples you notice that when one weight is twice the other, 

 its distance from the fulcrum is half that of the. other ; when it is three times 

 the other, its distance from the fulcrum is one-third that of the other ; and 

 when it is five times that of the other, its distance from the fulcrum is one- 

 fifth that of the other. 



In such cases the distances are said to be in inverse proportion to the 

 weights. 



C. Application of the Lever. 



10. Find where a boy must place his weight in 

 order to lift a certain object, as the desk, by means 

 of a lever. 



1 1. What is the effect of moving the fulcrum farther 

 from the object ? Why ? 



12. {a) Where must two boys, each the weight of the 



first, put their combined weight to just raise 

 the object ? 

 {b) Where must a boy half as heavy as the first 

 put his weight to raise the object ? 



13. Discover the application of the lever in the use of 

 the claw-hammer, wrench, button-hook, auger. 



14. If a boy weighing eighty pounds places his weight 

 ten feet from the fulcrum, the weight lifted being two 

 feet from the fulcrum, find the greatest weight he can 

 lift. 



15. What weight placed 8 feet from the fulcrum will 

 balance 24 lbs, placed 3 feet from it ? 



