224 PROBLEMS-FOOD ECONOMY Various foods furnish different amounts of nutriment, so that a food costing little may be of high value and vice versa. For example, 1 lb. of round beefsteak contains 5 oz. of nutriment, and a pound of stew beef 12 oz. The steak will cost about 14¢ a pound and the stew beef 54. 1. A pound of sirloin of beef costing 20¢ a pound furnishes 2.5 oz. of protein or nourishment, and 1 lb. of fresh codfish costing 10¢ furnishes 1.8 oz.; which is the cheaper food, sirloin or codfish? The table shows the amounts of various foods that 10¢ will buy and the respective amounts of nourishment furnished: 2. Which article of food furnishes the most protein for the same cost? The most fat? The greatest number of energy or heat units? Make 10 other problems. PROBLEMS-FORCE OF WINDS 225 1. Claude let his toy balloon ascend by a string. A light breeze carried the balloon along at the rate of 2 mi. per hour. He followed the balloon for 40 minutes; how many miles did he walk? 2. A strong wind blowing 20 mi. per hour blew Mark's hat across a ravine. The hat was carried along a minute before it landed; how far was it carried in miles? In yards? In feet? 3. Charlotte sailed her boat in a breeze blowing 7 mi. per hour. The boat moved only as fast as the wind; how far did she sail in an hour? In 45 min.? 4. From the dimensions given in the picture, find the area of the 6 FT. 4 FT. 8 FT. IFT. -IN sail of the boat. When a breeze of 7 miles per hour blows directly against a surface it exerts a pressure of .23 lb. per square foot. Find the total pressure on the sail of the boat. 5. Find the total area of the sails on this ship. When a strong wind exerts a pressure of 1.62 lb. per square foot, what is the total pressure on these sails? 6. A strong wind blows at the rate of 18 mi. per hour. If a schooner sailing in such a wind goes as fast as the wind, how many miles does it sail in 2 hours? 7. How long does it take a violent gale blowing at the rate of 58 mi. an hour to cross Lake Michigan where it is 65 miles wide? 8. From Ludington to Milwaukee across Lake Michigan is 91 miles; how long would it take a gale blowing 45 mi. per hour to travel from Ludington to Milwaukee? 226 PROBLEMS-FORCE OF WINDS 1. Find from the following table the pressure exerted on 2 sq. ft. of surface by each of the winds named. 2. Find how many pounds pressure each wind would exert in blowing directly against the side of a house 50 ft. long and 18 ft. high. 3. A railroad engine is running directly against a high wind. If the surface exposed to the wind is 55 sq. ft., how 20 14 FT. many pounds pressure from the wind does the engine overcome? 4. The surface enclosed by dotted lines in the picture represents the area of the side of a haystack; how many square feet are there in this surface? How many pounds pressure would each kind of wind given in the table exert on the haystack in blowing directly against this surface? 5. A strong wind carries a balloon along for 5 hr. at 27 mi. per hr.; how many miles is the balloon carried? 16 FT. 6. A hurricane blowing 76 miles per hour tore a shingle from a house, carried it for of an hour and dropped it at a distant village; how far from the house was the village? Make and solve problems using the following data: 1. The street-paving cost $1.50 per sq. yd. 2. The construction of the canal cost $.50 per sq. yd. 3. The equipment for lighting the streets cost $2,000 per mile. 4. The construction of sewers on every street cost at the rate of $1.00 per running foot. 5. It cost $3.50 per foot to construct the street-car line. 6. Land in blocks that border on the canal is worth 25¢ per sq. ft.; land elsewhere is worth 50¢ per sq. ft. 228 PROBLEMS-LIGHTING The picture shows the three dials of a gas-meter. figures on the dial at the right denote hundreds. When the The hand of this dial has made a revo lution the hand on the center dial points to 1; that is, it indicates 1 thousand feet. The figures on the dial at the left denote ten-thousands, and the hand moves one space as often as the center hand makes one revolution. In reading the center and left-hand dials, if the hand lies between two digits the smaller is taken as the reading, except between 9 and 0, where 9 is taken. On the right-hand dial it is customary to take the nearest digit. Thus, the meter in the picture reads 47,300. Note that the hand on the center dial turns in the opposite direction from those on the end dials. 1. The figure shows the state of the meter in Mr. Roe's house at each of 2 readings. Read the meter for each date. Thousand Thousand 9 JANUARY 5, 1904.. 10 Thousand FEBRUARY 6, 1904. 2. How much gas was consumed from Jan. 5, 1904, to Feb. 6, 1904? What was the cost of the gas at $1 per thousand |