1916 

 PHYSICS 



Friday 9:00 a.m. Two hours 



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 %i 



than ten questions. 



Group I 

 (Omit one question from this group.) 



1. Define density and specific gravity. How do they compare in value in the 



metric system ? How do they compare in value in the EngHsh system ? 



2. Upon a table stands a closed cubical box, measuring 15 cm. on each inside edge, 



above the top of which projects a tube 20 cm. high and 1 sq. cm. in area 



of inside cross-section. The box and tube weigh 200 gms. Both box and 



tube are filled with water. Find 



(a) the total force exerted upon the table; 



{b) the total force exerted by the water upon the bottom of the box. 



3. When supplied with 100 cubic feet of water per second, at a head of 45 feet, 



what horse-power is developed by a turbine water wheel having an effi- 

 ciency of 80 per cent? (One cubic foot of water weighs 62.4 pounds.) 



4. A trolley car starting from rest experiences a uniform acceleration. At 



the end of 20 seconds its speed is 15 miles per hour, 

 (a) What is its acceleration ? 

 {b) How far has it traveled ? 



c 



Group II 



{Omit one question from this group.) 



5. Given a gun, a stop watch, and a thermometer, how could the width of a 



lake be determined ? Show how the calculations should be performed. 



6. If two musical tones, one of 68 vibrations per second and the other of 70 



vibrations per second, are sounded at the same time, describe and explain 

 the effect produced. What name is given to this phenomenon ? 



Group III 

 {Omit one question from this group.) 



7. Describe an experiment, preferably one which you have personally per- 



formed, by which the heat changes occurring during a change of state, 

 such as from a liquid to a solid, may be shown. Explain the results 

 obtained. 



8. A steel projectile is moving with a speed of 700 meters per second at the 



instant that it strikes a target. Assuming that all of the energy of motion 

 is transformed into heat in the projectile, calculate its rise of temperature. 

 Take the specific heat of steel as . 12 and the mechanical equivalent of 

 heat as 41,800,000 ergs. *» 



9. The air in an automobile tire has a pressure of 80 pounds per square inch at 



a temperature of 15°C. If, after the car has been driven, the temperature 

 of the air in the tire has risen to 32° C., what is the air pressure in the tire ? 



(SEE NEXT PAGE) 

 io6 



