An aircraft component is fabricated from an aluminum alloy that has a plane strain fracture toughness of 36 . It has been determined that fracture results at a stress of 225 MPa when the maximum (or critical) internal crack length is 2.44 mm. Determine the value of for this same component and alloy at a stress level of 337 MPa when the maximum internal crack length is 1.22 mm.

What is creep? what is stress relaxation?

An electric kettle is made out of stainless steel, weighs two pounds (when empty) and is equipped with a heating element that consumes 2 kw of electricity. assuming that the water and the kettle are at the same uniform temperature at any moment of time, calculate the shortest possible time to bring 2 quarts of water from room temperature to the onset of boiling

Apiping systems consists of 6 m of 6-std type k and 12 m of 4-std type k, both drawn copper tubing. the system conveys ethylene glycol at a rate of 0.013 m3/s. the pressure drop across the system is to be calculated. there are two 90° elbows in the 6-in pipe, a reduction from the 6-in pipe to the 4-in pipe and four 90° elbows in the 4-in pipe. all fittings are soldered (same as flanged) and regular. the inlet and outlet of the system are at the same height.