Acenter-cracked panel with an initial crack length of 0.010 mm is subjected to a tensile cyclic stress between 25 and 125 mpa for 35 cycles. the panel is then subjected to a tensile cycle stress between 0 and 250 mpa. how many of the larger stress amplitude cycles can be sustained before failure? the material has a fracture toughness of 25 mpa√m and material constants n = 3.1 and c = 1.8 x 10-10 for these units.

Fluids at rest possess no flow energy. a)- true b)- false

Asolid cylinder is concentric with a straight pipe. the cylinder is 0.5 m long and has an outside diameter of 8 cm. the pipe has an inside diameter of 8.5 cm. the annulus between the cylinder ad the pipe contains stationary oil. the oil has a specific gravity of 0.92 and a kinematic viscosity of 5.57 x 10-4 m2/s. most nearly, what is the force needed to move the cylinder along the pipe at a constant velocity of 1 m/s?

Acertain flow of air (at stp) has a velocity distribution given by v i (in ft/s). if this flow is going through a 4 ft square area in the yz-plane (centered at the origin), what is the mass flow rate (in lbm/s)?