THERMODYNAMICS. 365 



9. To what temperature would a cannon-ball weighing 150 Ibs. 

 and moving 1920 feet per sec., warm 2000 Ibs. of water at 32 F., if 

 its motion were suddenly converted into heat ? 



10. (a.) How many pounds of water can be evaporated by 80 Ibs. 

 of pure carbon ? (&.) If applied to iron, how many pounds could b 

 heated from F. to 2000 F. 1 



11. With what velocity must a 10-ton locomotive move to give 

 a mechanical energy equivalent to the heat necessary to convert 

 48 pounds of ice at C. to steam at 100 C. ? 



12. An 8-lb. ball is shot vertically upward in a vacuum with a 

 velocity of 2000 feet. How many pounds of water may be raised 

 from the freezing to the boiling point by the heat generated when 

 it strikes the earth on its descent ? 



13. (a.) From what height must water fall in order to raise its 

 own temperature 1 C. by the destruction of the velocity acquired, 

 supposing no other body to receive any of the heat thus generated? 

 (Answer to be given in meters.) (&.) How far must mercury fall to 

 produce the same effect ? (Specific heat of mercury = ,0333.) 



14. With a velocity of how many cm. per second must a leaden 

 bullet strike c, target that its temperature may be raised 100 C. by 

 the collision, supposing all the energy of the motion to be spent in 

 heating the bullet ? (Specific heat of lead =.031 4; g. =980 cm. % 127.) 



15. A steam-engine raises a ton weight 386 ft. How many heat 

 units are thus expended ? 



16. A 64-pound cannon-ball strikes a target with a velocity of 

 1400 feet per second. Supposing all the heat generated to be given 

 to 60 pounds of water, how many centigrade degrees would the 

 temperature of the water be raised ? 



17. A cannon-ball weighing 7 pounds strikes an iron target with a 

 velocity of 1000 foet per second. Suppose the whole of the motion 

 to be converted into heat and the heat uniformly distributed through 

 70 pounds of the target, determine the change of temperature thus 

 produced. (Specific heat of iron = .1138.) 



18. The specific heat of tin is .056 and its latent heat is 25.6 Fah- 

 renheit degrees. Find the mechanical equivalent of the amount of 

 heat needed to heat 6 pounds of tin from 374 F. to its melting point 

 442 F. and to melt it. 



19. A lead ball strikes a target with a velocity of 1200 feet per 

 second. Show that the heat generated would be sufficient to fuse 

 the lead. (See 497 and 535. The latent heat of lead is 5.4 C.) 



20. The mechanical equivalent of heat is 772 foot-pounds, refer- 

 ence being made to the Fahrenheit degree. It is also given as 

 424 kilogrammeters, reference being made to the centigrade degree. 

 Show that the two values are approximately identical. 



