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 0.430 m (1.41 feet) with a rubber seal in between are placed together and air pumped out so that the pressure inside is 15.00 millibar. The atmospheric pressure outside is 940 millibar.
1. Calculate the force required to pull the two hemispheres apart. [Note: 1 millibar=100 N/m2. One atmosphere is 1013 millibar = 1.013×105 N/m2 ]
2. Two equal teams of horses, are attached to the hemispheres to pull it apart. If each horse can pull with a force of 1450N (i.e., about 326 lbs), what is the minimum number of horses required?

Answer 1

The force required to pull the two hemispheres apart is 4.2×10⁴ N and 29 number of horses are needed to pull these hemispheres apart.

What's the expression of force in terms of pressure?

• Mathematically, force = pressure/area
• Total area of the two hemispheres = 4π×(0.43)²= 2.3 m²
• Total pressure on the hemispheres= 15 milibar (directed inward) + 940 milibar (atmospheric pressure) = 955 milibar

=955×100 N/m²= 9.55×10⁴ N/m²

• Force on the hemispheres= 9.55×10⁴/2.3 = 4.2×10⁴ N

What's the minimum number of horses required to get 4.2×10⁴ N of force, if each horse can pull with a force of 1450N?

No. of horses required to separate the hemispheres = 4.2×10⁴/1450 = 29

Thus, we can conclude that the 29 horses are needed to pull the two hemispheres with a force of 4.2×10⁴ N.

Learn more about the pressure and force here:

brainly.com/question/8033367

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