A spherical pressure vessel is made of thin magnesium plate 0.25 cm thick. The main diameter of the sphere is 600 cm and allowable stress in tension is 900 kg/cm2. The safe internal gas pressure for the vessel would be
a) 0.5 kg/cm2
b) 1.5 kg/cm2
c) 4.5 kg/cm2
d) 5.7 kg/cm2
a) 0.5 kg/cm2
b) 1.5 kg/cm2
c) 4.5 kg/cm2
d) 5.7 kg/cm2