Conservation of Energy 



75 



flying off into space, where we should all be frozen to 

 icicles and lost in everlasting night. For if the sun's pull 

 stopped, the earth would fly off as does a stone whirled 

 from the end of a string, when you let go of the string. 



The moon, in like manner, would fly away from the 

 earth and sun if gravitation stopped pulling it, but it 

 would crash into us if its centrifugal force did not keep 

 it at a safe distance. 



Have you ever sat on a spinning platform, sometimes 

 called " the social whirl," in an amusement park, and 

 tried to stay on as it spun faster and faster? It is 

 centrifugal force that makes you slide away from the 

 center and off at the edge. 



How cream is separated from milk by centrifugal 

 force. The heavier things are, the harder they are 



FIG. 37. An automobile race. Notice how the track is banked to keep the cars 

 from overturning on the curves. 



