70 



MOTION OF PROJECTILES. 



not affected by the force of gravity ; but this force 

 causes the body, while moving horizontally, to move 

 downwards at the same time with continually in- 

 creasing velocity. In fig. 50 is represented the actual 

 path, reduced to TI^OIT^ f ^ s rea ^ magnitude, of a body 

 which has been projected horizontally with a velocity of 



784 





90.4 



4-I-.1 



FIG. 51 (^ real size). 



12 m . The body would thus move horizontally through 

 12, 24, 36, 48 m in 1, 2, 3, 4 seconds, and arrive at the 

 ends of these intervals of time at B, C, D, E respec- 

 tively. But gravity causes the body during these 

 intervals also to move downwards through 4 m *9, 

 19 m '6, 44 m -l, 78 m -4, so that the body actually arrives 

 at F, G, H, I at the end of the successive seconds. Fig. 

 51 represents on the same scale the path of a body pro- 



