The surface of a steel gear of 1022 steel (0.22 wt % C ) is to be gas-carburized at 927 oC. Calculate the time necessary to increase the carbon content to 0.3 wt% at 0.015 in. below the surface of the gear. Assume the carbon content of the surface to be 1.20wt%. D (C in iron ) at 927 oC = 1.28 x 10-11 m2/s. The answer should have one decimal of accuracy and be in minutes.

In a system with only a single force acting upon a body, what is the relationship between the change in kinetic energy and the work done by the force? answers: work is equal to the change in kinetic energy.work depends on the square of the change in potential energy.work is equal to the negative of the change in kinetic energy.work is equal to the square of the change in kinetic energy