IQI2 



PHYSICS 



Monday 3 . 45-5 . 45 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. (a) Explain the meaning of the terms momentum and moment of force. 



(b) Describe an experiment, preferably one which you have personally 

 performed, by which the coefficient of sliding friction between two 

 surfaces may be found and indicate the manner in which the numerical 

 value of the coefficient may be computed from the data obtained. 



2. A diving bell, or a caisson, is lowered into a lake until the surface of the water 



within it is 690 centimeters below the surface of the lake. What does 

 one cubic centimeter of air within the bell weigh if, at the surface of the 

 lake, where the barometric reading is 76 centimeters, one cubic centi- 

 meter of air weighs o. 0012 g. ? (The density of mercury is 13 . 6). 



3. A bucket of water weighing 30 pounds is to be raised from a well 20 feet deep 



by means of a windlass having an efficiency of 80 per cent. If the crank 

 arm is 15 inches long and the drum on which the rope is wound is 6 inches 

 in diameter how great an effort must be applied at the crank and through 

 what distance must it act ? 



4. A power boat is equipped with a motor which develops 10 horse-power when 



propelling the boat at the rate of 15 miles per hour (22 feet per second). 

 Calculate the resistance which the boat encounters when propelled at this 

 speed, assuming that all of the work done by the motor is that required 

 to overcome the resistance of the water. 



GROUP B 

 Omit one question from this group 



5. Describe some common form of resonator and explain resonance as illus- 



trated by its action. 



6. A train running 60 miles per hour (88 feet per second), strikes two torpedoes 



placed on the track 352 feet apart. What time interval occurs between 

 the reports as hear at a station which the train is approaching, the temper- 

 ature of the air being 20 C. ? 



