How much force is required to accelerate a 5 kg mass at 20m / s2?

An observer that stands still as the electron moves by him, will observe

How do you tell if someone actually cares about you? and just say they do?

Carbon is allowed to diffuse through a steel plate 15 mm thick. the concentrations of carbon at the two faces are 0.65 and 0.30 kg c/m^3 fe, which are maintained constant. if the preexponential and activation energy are 6.2 x 10-7 m2 /s and 80,000 j/mol, respectively, compute the temperature at which the diffusion flux is 1.43 x 10^-9 kg/m^2 -s.