IQI4 



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. Why is it easier to roll a barrel up a long board into a wagon than to lif t it 



vertically ? 



How does the work done against gravity when the barrel is rolled up the 

 board compare in amount with the work required to lift it vertically ? 



2. At what depth in a lake will a bubble of air have one-half the volume that 



it has on reaching the surface when the barometric height at the surface 

 is 73 centimeters? (The density of mercury is 13.6.) 



3. A 5-lb. weight is hung from one end of a uniform bar of wood 4 ft. long and 



weighing 6 Ibs. At what point must the bar be supported to balance in a 

 horizontal position? 



4. A ball is thrown up and 5 seconds later is caught. 



a) How high did it rise ? 



b) With what velocity did it return to the hand ? 



GROUP B. (Omit one question from this group.) 



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



formed, by which the pitch of a musical tone may be determined. 



6. An observer sets his watch by the report of a signal gun one mile away. 



Find, to one-tenth of a second, the allowance that he should make on 

 account of the distance of the gun, the temperature of the air being 20 C. 



GROUP C. (Omit one question from this group.) 



7. Explain the construction and operation of some form of refrigerating appa- 



ratus as used for making artificial ice or for cooling rooms. 



8. What is meant by the specific heat of a substance ? 



A piece of nickel weighing 200 grams at temperature 98 C. was dropped 

 into 500 grams of water at temperature 18 C. The resulting tempera- 

 ture was 21.4 C. Find the specific heat of nickel. 



9. The volume of a body of gas at 27 C. is 100 cubic centimeters. If the pres- 



sure on the gas is doubled to what temperature must it be heated in order 

 to maintain the volume constant ? 



60 



