152 FARM ARITHMETIC. 



pounds. Thus a horse weighing 1,800 pounds may readi- 

 ly pull a wagon and load of one ton horizontally, since this 

 would require a pull of not more than 150 pounds. He 

 can keep this up indefinitely, working ten hours per day 

 and walking at the rate of 2.5 miles an hour. A 1,200- 

 pound horse should be required to do only about two- 

 thirds of this amount of work per day. 



514. How much power is a horse developing when 

 walking 2.5 miles an hour, and exerting a steady pull on 

 his traces of 150 pounds? 



Process : 



150 X 5,280 X 2.5 



= 1 horsepower. 

 33,000 X 60 



515. How many horsepower is a horse developing 

 when walking 2.5 miles an hour with a steady pull on 

 his traces of 100 pounds ? 



516. How many horsepower is a horse developing 

 when walking four miles an hour and pulling 75 pounds ? 

 90 pounds? 165 pounds? 



517. A horse is walking 2.5 miles an hour and pulling 

 100 pounds on his traces. How fast should he walk to 

 develop the same power if his load is increased to a pull 

 of 150 pounds? 



518. A certain horse can readily draw 100 pounds 

 when walking 2.5 miles an hour. How rapidly may he 

 travel if he has a pull of but 25 pounds? 50 pounds? 

 75 pounds ? 200 pounds ? 



519. How rapidly with a pull of 150 pounds, if he is 

 permitted to rest one-half of the time? With a pull of 

 200 pounds? 



