Suppose that all the dislocations in 3000 mm3 of crystal were somehow removed and linked end to end. Given 1 m =0.0006214 mile, how far (in miles) would this chain extend for dislocation densities of (a) 10^4 mm^-2 (undeformed metal)? (b) 10^10 mm-2 (cold-worked metal)?

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?