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Common Science 



FIG. 34. When the paper is jerked out, the glass of water does not move. 



hand of the one who caught it as when it left your hand 

 or the bat. 

 Try these experiments : 



Experiment 23. Fill a glass almost to the brim with water. 

 Lay a smooth piece of writing paper 10 or n inches long on 

 a smooth table, placing it near the edge of the table. Set 

 the glass of water on the paper near its inner edge (Fig. 34). 



Take hold of the edge of the paper that is near the edge 

 of the table. Move your hand a little toward the glass so 

 that the paper is somewhat bent. Then, keeping your 

 hand near the level of the table, suddenly jerk the paper 

 out from under the glass. If you give a quick enough jerk 

 and keep your hand near the level of the table, not a drop 

 of water will spill and the glass will stay almost exactly 

 where it was. 



This is because the glass of water has inertia. It was 

 standing still, and so it tends to remain standing still. 



