Astructural component in the form of a wide plate is to be fabricated from a steel alloy that has a plane-strain fracture toughness of and a yield strength of 860 mpa. the flaw size resolution limit of the flaw detection apparatus is 3.0 mm. if the design stress is one-half the yield strength and the value of y is 1.0, determine whether a critical flaw for this plate is subject to detection.

Asheet of steel 1.5 mm thick has nitrogen atmospheres on both sides at 1200oc and is permitted to achieve a steady-state diffusion condition. the diffusion coefficient for nitrogen in steel at this temperature is 6 x 10- 11 m2 /s, and the diffusion flux is found to be 1.2 x 10-7 kg/m2 -s. also, it is known that the concentration of nitrogen in the steel at the high-pressure surface is 4 kg/m3 . how far into the sheet from this high-pressure side will the concentration be 2.0 kg/m3 ? assume a linear concentration profile.

I'm thinking it's 2 you are asked to explain the earth's magnetic field. which is the best reply? 1. the earth's magnetic south is similar to the north pole of a magnet. 2. the earth's core has a strong magnetic charge similar to the south pole of a magnet. 3. the earth's geomagnetic south is similar to the south pole of a magnet. 4. the earth's magnetic charge is not centered at either pole; it varies based on location.

Explain what it means to view something from a frame of reference. provide an example that illustrates your explanation. (4 points)