Question

In 1656, the Burgmeister (mayor) of the town of Magdeburg, Germany, Otto Von Guericke, carried out a dramatic demonstration of the effect resulting from evacuating air from a container. It is the basis for this problem. Two steel hemispheres of radius 0.380 m (1.25 feet) with a rubber seal in between are placed together and air pumped out so that the pressure inside is 11.00 millibar. The atmospheric pressure outside is 950 millibar. Calculate the force required to pull the two hemispheres apart. [Note: 1 millibar=100 N/m2. One atmosphere is 1013 millibar = 1.013x105 N/m2] Submit Answer Tries 0/20 Two equal teams of horses, are attached to the hemispheres to pull it apart. If each horse can pull with a force of 1360N (i.e., about 306 lbs), what is the minimum number of horses required? Submit Answer Tries 0/20

Answer 1

Soll Given: radius of Hemisphere , r=0.38om Pressure inside, Pi= 11 milli bar Pressure outside Po=950 milliben. R 1 millibar = 100 N/m2 force = Pressurex Area - ___ ("Areaa042 Force required to get hemisphere Apart F = Net pressure x Area E = (Po-Pi) ar? = (350-11) x 100 x 3074 x 10.38072 If = 42575.76N Force provided by one hisse = 1360N Number of herse required N = 42575. 76 - 31:3_ 1360 IN = 32 Horses 32 horse required seperate apart to get hemisphere.