Transient heating of a concrete wall. a wall made of concrete 0.305 m thick is insulated on the rear side. the wall at a uniforin temperature of 10°c (283.2 k) is exposed on the front side to a gas at 843°c (1116.2 k). the convection coefficient is 28.4 w/m².k, the thermal diffusivity is 1.74 x 10" mº/h, and the thermal conductivity is 0.935 w/ m k . (a) calculate the time for the temperature at the insulated face to reach 232°c (505.2 k). (b) calculate the temperature at a point 0.152 m below the surface at this same time.

The earth's moon is unusually large. two popular theories of the moon's origin include the "sister world" hypothesis, which states that the moon formed from the same materials as the earth, near enough to the earth that they fell into orbit around each other. a second theory is the "capture" hypothesis, in which the moon formed elsewhere in the solar system, and the earth's gravity pulled it into its orbit. studies of what the moon is made of indicate that some of its materials had to come from the earth or from the same area of the solar system where the earth had formed. at the same time, the moon does not contain much of the material that makes up the earth's core, so the moon could not have formed from the same materials as the earth. how do the two facts above affect the described theories of the moon's origin? a. they show that scientists will never agree on where the moon came from. b. they show that more experiments on moon formation need to be done. c. they show that no theory accounts for the existence of the moon. d. they show that neither theory is complete and entirely correct.

Calculate the number of moles of ethane in 100 grams

Suppose the universe were completely empty except for one object-a solid sphere moving through space of 100 km/s. what sort of path would the object be moving in? explain your answer