If Vector A is (6, 4) and Vector B is (-2, -1), what is A – B? A. (4,5)
B. (4,3)
C. (8,3)
D. (8,5)

Phase changes are chemical changes. true or false

There are weak or strong attractive forces between atoms of liquids with a high viscosity

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.