Apole is subjected to two loads, pi and p2 so that the bending moment at the bottom of the pole is p1 m, 30p-20p here, pi is normal random variable with mean 50kn and standard deviation 5 kn; p2 is another normal random variable with mean 20 kn and standard deviation 3 kn. (a) determine the mean and standard deviation of the bending moment at the bottom of the pole; (b) if the moment-resisting capacity at the bottom of the pole is mr, a normal random variable with 0m mean 1750 kn-m and standard deviation of 150 kn-m, what is the probability p2 30m that the pole will fail under the loads pi and p2? what is the associated reliability index?