In some areas in northern Virginia the frequency of the blac…

In some areas in northern Virginia the frequency of the black phase of the gray squirrel (Sciurus carolinensis) is 25%.  One thought is that the black coloration helps protect squirrels from predators (more difficult to see in shady areas).  You find that over the course of a year 23 out of 67 gray squirrels are caught by predators, whereas for black squirrels 13 out of 57 squirrels are caught by predators. What is the overall probability of any squirrel surviving? (Just FYI – not important for answering the question – black squirrels are the result of a single allele change – sort of like black leopards or black jaguars).

A load of 15 kN is applied through a pin connection and a sq…

A load of 15 kN is applied through a pin connection and a square bearing plate to the end of a beam that has a rectangular cross section. The base of the beam’s cross section is 74 mm and the height is 140 mm. The size of the bearing plate is 94 mm. Determine the bearing stress between the plate and the beam.

Before an automotive engine is started, its timing belt has…

Before an automotive engine is started, its timing belt has a length of 43.00 in. and a temperature of 70°F. At the engine operating temperature of 210°F, it is determined that the belt has elongated to 43.04 in. What is the coefficient of thermal expansion of the belt?