With all other variables being held constant, increasing the wall thickness of a spherical pressure vessel will : a) increase the axial stress
b) decrease the radial stress on the inner surface
c) increase the radial stress on the inner surface
d) decrease the axial stress

At 12 noon, the count in a bacteria culture was 400; at 4: 00 pm the count was 1200 let p(t) denote the bacteria cou population growth law. find: (a) an expression for the bacteria count at any time t (b) the bacteria count at 10 am. (c) the time required for the bacteria count to reach 1800.