210 ANSWERS TO PRACTICAL QUESTIONS 



on the finger when the loaded end is upward than when it 

 is downward. 



When the loaded end is upward a slighter motion is 

 needed to bring the line of direction within the base. 

 The principle is similar to that of the balancing pole of 

 the gymnast. 



49. What effect would the fall of a heavy body to the 

 earth have upon the motion of the earth in its orbit? 



If its line of fall was exactly opposed to the direction 

 of the earth's motion, it would, by its momentum, tend 

 to retard the earth. If its line of fall was exactly in the 

 direction of the earth's motion, it would increase the 

 earth's velocity. If its line of fall was transverse to 

 the direction of the earth's motion, it would deflect the 

 earth from its orbit. All of these changes would, of 

 course, be infinitesimal in amount. 



50. If a body weighing i Ib. on the earth were carried 

 to the sun, it would weigh 27 Ibs. How much would it 

 attract the sun ? 



Ans. 27 Ibs. 



5 1. Why does watery vapor float and rainfall? 



(See Physics, p. 116, Question 13.) 



The vapor of water is lighter than water itself, as the 

 particles are pushed so far apart by the repellent force 

 heat. 



52. If a body weighs 10 kilos, on the surface of the earth, 

 what will it weigh 1,000 km. above? 



x: 10 kilos. :: (6,366 *) 2 : (7.366)2 

 x 7.5 kilograms. 



* The radius, or semi-diameter of the earth, is given by French astronomers 

 at 6,366 km. 



