1.A 4ft-long, 1-in-diameter shaft rotates inside an equally long cylinder that is 1.02 in. in diameter. Calculate the torque required to rotate the inner shaft at 2000 rpm if SAE-30 oil at 70 degrees F fills the gap. Also, calculate the horsepower required. Assume concentric cylinders.
2.For a sample of 60 , compute the Weibull, Hazen and Cunnane plotting probabilities and the corresponding return periods for the two largest and two smallest rank.Comment on the result.
3.Assuming a density of 120 lb/ft*3 for masonry brickwork,determine the maximum height of a brick wall if the allowable compressive stress is limited to 150 psi,and the brick is (a) four inches wide and (b) six inches wide.