In the Fourier heat equation we have dT/dt = alpha * (d^2T/dx^2), with alpha being the proportionality constant. What I do understand is the relation between derivatives of x and t, but why the proportionality constant? How does it even make sense?

You are a sales representative for a company that makes a new alternate fuel for vehicles. you have prepared a presentation for the environmental engineers to sell your new product. what question do you expect the audience to ask regarding whether the new fuel will cause less damage to the environment? a. do we have to change any parts of the vehicle to use this alternate fuel? b. will the vehicles get better fuel mileage with the alternate fuel? c. how much greenhouse gas does your fuel produce compared with current fuel sources? d. is the alternate fuel more expensive than fossil fuel?

What conclusion can be made based on the temperature of soil when the light hits the soil at 0°, 45°, and 90° angles in section 2 of the experiment? did your results support your hypothesis? why or why not?

The molecular mass of a gas is (select all that apply) a. independent of the type of gas b. the same number as the atomic (or molecular) mass, but measured in grams c. dependent on the temperature d. the mass of a mole of the gas