1.In a study it was found that 39% of the bacteria died within 9 hoursand 67% died within 20 hours. If the rate of andwer proportional to the number remaining, how long would it take to obtain a 99.9% reduction in the bacteria?
2.Find the maximum shearing stress and its location in the shaft and the angle of twist of A with respect to C. Let G = 4x10^6 psi for the entire shaft.