REVIEW. 437 



5. (a.) Explain the parallelogram of forces, and (6.) the polygon 

 of forces. 



6. (a.) Define gravitation and give its laws. (6.) Give the law of 

 weight, (c.) What is the centre of gravity, and how may it be 

 found ? 



7. (a.) Describe Att wood's machine. (5.) Give the rules and 

 formulas for falling bodies, (c.) How far will a body fall in three 

 seconds ? 



8. (a.) What is a pendulum ? (&.) Give the laws of the pendulum, 

 (e.) How long must a pendulum be to vibrate 10 times a minute ? 



9. (a.) Define energy, foot-pound, dyne, erg, and horse-power. 

 (6.) Deduce the formula for measuring kinetic energy when weight 

 and velocity are given. 



10. (.) Define each of the six traditional simple machines. (6.) 

 Give the law for each, (c.) What is the office of a machine ? (d.\ 

 Discuss the subject of friction. 



11. (.) Give Pascal's law, and the rule for determining lateral 

 liquid pressure. (6.) Describe the hydrostatic press, and state the 

 general principle upon which its action depends. 



12. (a.} State Archimedes' principle. (6.) What is specific gravity ? 

 (c.) Explain the determination of the sp. gr. of a solid lighter than 

 water, (d.) Explain the use of the specific gravity bulb, (e.) 

 Describe Nicholson's hydrometer and explain its use. 



13. (a.) A 1000 gr. bottle having in it 928 grs. of water, has the 

 remaining space filled with metallic sand and then weighs 1126.75. 

 What is the sp. gr. of the sand ? (5.) Through which of the three 

 kinds of levers can the greatest power be gained ? (c.) Through 

 which can none be gained ? (d.) Why do we use it ? (e.) Give an 

 example. 



14. A ball projected vertically upward, returns in 15 seconds to 

 the place of projection. How far did it ascend ? 



15. (a.) A floating solid displaces how much liquid ? (6.) An 

 immersed solid displaces how much liquid ? (c.) A floating solid 

 loses how much weight ? (d.) An immersed solid loses how much 

 weight ? 



16. What is the energy of a rifle-ball weighing 32 grams, having 

 a velocity of 213 meters per second, and striking in the centre of a 

 pendulum of wood weighing 23 kilograms? 



17. (fi.) What is meant by the increment of velocity or gravity ? 

 (6.) How far will a body fall in 6| seconds? (e.) How far in the 

 9th second? (a.) If a freely-falling body have a velocity of 448 ft. 

 per second, how long has it been falling ? 



18. (a.) Deduce, from the laws of falling bodies, the formula for 



