528 FARM AND SCHOOL PROBLEMS. 



11. A binder cuts a strip ^ of a rod wide around a square ten 

 acre field; what part of an acre is cut in one round? In two rounds? 



12. If a strip of land containing wheat is 160 rods long and 20 

 rods wide, how many times will a team have to turn at the ends in cutting 

 this field of wheat if the binder cuts off 6 feet and 8 inches on an average? 



13. If the same number of acres as given in problem 12 is divided 

 into two square fields, what will be the number of turns in the two fields 

 with a binder cutting 6 ft. 8 inches wide? 



14. How many miles must a binder travel in cutting a strip 7 feet 

 wide, to cut 5 acres? 



Farm Mechanics. 



In the study of Agriculture we may regard the word work 

 to mean overcoming resistance. 



1 . A force must produce motion to do work. 



2. To calculate work by arithmetic it is necessary to weigh the 

 object and to measure the distance it is moved. 



3. To lift a pound weight one foot is called a pound of work 

 or a foot-pound. 



4. To lift a weight of 25 pounds one foot, requires 25 foot-pounds. 



5. To lift a weight of 25 Ibs., 4 feet requires 4x25 foot-pounds or 

 100 foot-pounds. 



PROBLEMS. 



1. If a weight of 4 Ibs. is moved 25 feet, what is the required 

 amount of work? 



2. If a team hauling a load exert an average pull of 200 pounds, 

 what will be the work done in pulling the load 10 miles? 10x5,280x 

 200 = 10,560,000.) 



Therefore, to lift a pound I ft. vs. gravity or to move a 

 body in any direction, when the force necessary to do this is equal 

 to that required to lift I lb., is I foot-pound. 



Therefore, 



Work equals force multiplied by distance. 



Energy is the power of doing work, and power is the rate 

 of doing work. 



If a horse can do more work than a man it is because he has 

 more energy and power. 



