To remove a tight-fitting lid from a jar, Megan runs the lid under hot water. What happens to the Jar lid when its temperature increases?
A. The temperature increases, and the lid expands
B. The temperature decreases, and the lid contracts.
C. The potential energy increases, and the lid contracts.
D. The potential energy decreases, and the lid expands

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.