92 FIRST YEAR COURSE IN GENERAL SCIENCE 



depth of 25 cm. above the top of the block. State (a) the depth of the 

 bottom of the block; (6) the average depth of each side; (c) the pres- 

 sure in grams on the top; (d) the pressure in grams on the bottom; 

 (e) the pressure in grams on each side; (/) the difference in pressure on 

 the bottom and the top. Illustrate by a diagram. 



6. (a) How many cubic centimeters of water are displaced by the 

 block described in Ex. 5? (6) Compare this with the answer to Ex. 5, /. 



7. If the block described in Ex. 5 weighs 280 g. in air, what is its 

 weight in water? 



8. If the downward pressure on the tube admitting water to the 

 cylinder of an elevator is 100 Ib. to the square inch, what will be the 

 upward pressure on the large piston, if it is one square foot in area? 



9. Why is it easier to float in salt water than in fresh water? 



10. Why is a cloth better than a newspaper to wipe up water? 



11. Describe the surface of good blotting paper and tell why such 

 a surface is required. 



