An aluminum rod if 20 mm diameter iselongated 3.5 mm along its
longitudinal direction by a load of 25kn. if the modulus of
elasticity of aluminum is e = 70 gpa, determine the original length
of the bar.

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?

Brief discuss how the presence of dislocations in crystal structures can be an advantage and a disadvantage to engineer and designers.