A thick oak wall, initially at 25 oC, is suddenly exposed to combustion products for which T[infinity] = 800 oC and h = 20 W/m^2 ⋅ K. (a) Determine the time of exposure required for the surface to reach the ignition temperature of 400 oC.
(b) Plot the temperature distribution T(x) in the medium at t = 325 s. The distribution should extend to a location for which T ≈ 25 oC.

Afisherman notices that his boat is moving up and down periodically without any horizontal motion, owing to waves on the surface of the water. it takes a time of 2.20 s for the boat to travel from its highest point to its lowest, a total distance of 0.670 m . the fisherman sees that the wave crests are spaced a horizontal distance of 5.80 m apart. (a) how much is the wavelength? (b) find the period of the wave. (c) how fast are the waves traveling? (d) what is the amplitude a of each wave?

Observations show that interstellar clouds can have almost any shape and

Estimate the change in the gibbs energy and molar gibbs energy of 1.0dm3 of octane when the pressure acting on it is increased from 1.0 atm to 100 atm. the mass density of octane is 0.703 g cm−3