A balloon has a volume of 3.1 L at a pressure of 1.4 atm and a temperature of 33 ∘C. If the balloon is submerged in water to a depth where the pressure is 4.8 atm and the temperature is 15 ∘C, what is its volume (assume that any changes in pressure caused by the skin of the balloon are negligible)?

answerca air mass;

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.