In a lecture demonstration, a professor pulls apart two hemispherical steel shells (diameter D) with ease using their attached handles. She then places them together, pumps out the air to an absolute pressure of p, and hands them to a bodybuilder in the back row to pull apart.
(a) If atmospheric pressure is Po how much force must the bodybuilder exert on each shell?
(b) Evaluate your answer for the case P = 0.025 atm, D = 10.0 cm.