Question:
Two hemispherical shells can be pressed together to form a airtight sphere of radius 40cm. Suppose the shells are pressed together at a high altitude, where the air pressure is half its value at sea level. The sphere is then returned to sea level, where the air pressure is 105Pa. What force F, applied directly outward to each hemisphere, is required to pull them apart?
(A) 25,000N.
(B) 50,000N.
(C) 100,000N.
(D) 200,000N.
(E) 400,000N.