4. Construct a cardboard working-model showing the action of the gas engine and be prepared to explain the action of the various parts.
5. If 500 lbs. of iron should fall 2000 ft. and all of the resulting mechanical kinetic energy should be transformed into heat, what would be the amount of heat produced?
6. What are the special advantages of (a) the gasoline engine? (b) the turbine? (c) the reciprocating steam engine?
7. Do you burn coal or gas in your kitchen stove at home? Which is for you the more economical? Why?
8. What are the advantages of using a fireless cooker?
9. What is the efficiency of a locomotive that burns 3.2 lbs. of coal per horse-power-hour?
10. A gas engine developed in a test 0.34 horse-power for 1 minute. and 50 seconds, 0.5 cu. ft. of gas being used. The heat of combustion of the gas was 600 B.T.U. per cu. ft. Find the efficiency of the engine.
11. Find the horse-power of an engine, the diameter of the piston being 19 in., stroke 26 in.; it uses steam at an average pressure of 200 lbs. per square. inch and makes 100 strokes a minute.
12. What is the efficiency of an engine and boiler that develops 200 horse-power, while burning 390 lbs. of soft coal per hour?