Two-dimensional, steady-state conduction occurs in a hollow cylindrical solid of thermal conductivity 14 w/m·k, outer radius 1 m and overall length 5 m, where the origin of the coordinate system is located at the midpoint of the center line. The inner surface of the cylinder is insulated, and the temperature distribution within the cylinder has the form , where -20°c, 150°c/m2, -14°c, -300°c/m2 and and are in meters. (a) determine the inner radius of the cylinder. (b) determine the volumetric rate of heat generation, (c) determine the axial distribution of the heat flux at the outer surface, what is the heat rate at the outer surface? Is it into or out of the cylinder?

Researchers conducted an experiment to identify the effects of three different hand sanitizers on the growth of bacteria. the researchers grew one type of bacteria in twenty-four identical covered petri dishes. then, they opened eighteen petri dishes and applied the three hand sanitizers to six petri dishes each. they left the remaining six petri dishes closed as a control group. when the researchers measured the growth of bacteria two days later, the six dishes that had no hand sanitizer showed the least amount of bacterial growth. the researchers concluded that not using any hand sanitizer would lead to the least bacterial growth. which statement best explains why the researchers’ conclusion was not justified? the experiment tested too many variables. the control group was not treated the same as the experimental group. the sample size of twenty-four petri dishes is not large enough. the single type of bacteria is not adequate to make any conclusions.