Which statement best describes how the use of gasoline in a car relates to the discipline of chemistry?

a.) the materials used come from the ground.
b.) the gasoline undergoes a change as it burns.
c.) a car uses the gasoline to move.
d.) all parts of the car are composed of chemicals.

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.