WHEN DO WE WORK? 



291 



say to your shoulders instead of to the level of the table, 

 you would do twice the work, because while you would exert 

 the same force, you would continue it through double the 

 distance. 



Lifting heavy weights through great distances is not the 

 only way in which work is done. Painting, chopping wood, 

 hammering, plowing, washing, scrubbing, sewing, are all forms 

 of work. In painting, the 

 moving brush spreads paint 

 over a surface ; in chopping 

 wood, the descending ax 

 cleaves the wood asunder; 

 in scrubbing, the wet mop 

 rubbed over the floor car- 

 ries dirt away; in every 

 conceivable form of work, 

 force and motion occur. 



A man does work when 

 he walks, a woman does 

 work when she rocks in a 



FIG. 154. Crude method of farming. 



chair although here the 

 work is less than in walk- 

 ing. On a windy day the work done in walking is greater than 

 normal. The wind resists our progress, and we must exert more 

 force in order to cover the same distance. Walking through a 

 plowed or rough field is much more tiring than walking on a 

 smooth road, because, while the distance covered may be the 

 same, the effort put forth is greater, and more work is done. 

 Always the greater the resistance encountered, the greater the 

 force required, and the greater the work done. 



The work done by a boy who raises a 5-pound knapsack to 

 his shoulder would be 5x4, or 20, providing his shoulders 

 were 4 feet from the ground. 



ClARK INTRO. TO SC. IQ 



