IQI3 



PHYSICS 



Monday 2-4 p. m. 



A teacher's certificate covering the laboratory instruction must be presented as part 

 of the examination. 



Answer ten questions as indicated below. No extra credit will be given for more 

 than ten questions. 



GROUP A 

 Omit one question from this group 



1. Describe the hydrometer as used in determining the specific gravity of a liquid. 

 If the scale on the hydrometer is such that the specific gravity may be read 



directly from it, will the smaller numbers appear at the top of the scale, or 

 will they be found at the bottom ? Give the reasoning involved in your 

 answer. 



2. A boy drags a sled by exerting a force of 6 pounds on a rope reaching from his 



arm to the sled, a distance of 5 feet, his arm being 3 feet higher than the 

 sled. What part of the force that he is exerting is effective in dragging 

 the sled forward ? 



3. A pail 20 centimeters in diameter at the bottom, 30 centimeters in diameter 



at the top, 22 centimeters high, inside measurements, and weighing 1.5 

 kilograms stands, full of water, upon a table. The capacity of the pail is 

 10.943 liters. Calculate (a) The total pressure, due to the water, on the 

 bottom of the pail, (b) The total pressure of the pail and contents against 

 the table. 



4. A straight, uniform stick of timber 10 feet long, weighing 6 pounds per foot of 



length, lies on level ground. Applying his hands to one end of the stick a 

 man lifts this end 4 feet above the ground, vertical measure. How much 

 work does the man perform against gravity ? 



GROUP B 

 Omit one question from this group 



5. In what three respects, exclusive of duration, may musical tones differ from 



each other ? Explain the causes of these differences. 



6. When the velocity of sound, in air, is 1120 feet per second how many vibra- 



tions per second are necessary for the formation of sound waves 4 feet long ? 

 Determine the temperature of the air at the time of the experiment. 



GROUP C 

 Omit one question from this group 



7. Explain the meaning of the term Mechanical Equivalent of Heat. Describe 



an experimental method by which its numerical value has been determined. 



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