Explain why no work has been done after Ethan pushes against a brick wall for 5 minutes that did not move.
A. The wall does not contain inertia.
B. Three or more people are needed in order for work to be done.
C. Two or more people are needed in order for work to be done.
D. In order for work to be done, the wall needs to move.

Two technicians are discussing a resistance measurement between the can-h and can-l wires. technician a says this measurement should be done with the ignition switch in the "run" position. technician b states that a measurement of 0 ohms indicates an open in the network. which technician is correct?

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.

Distinguish between linear momentum and angular momentum