At sea level the volume of a hot air balloon is 1.00 x 10 liters. The pressure is 760. temperature is 25.0°C. At an altitude of 6.00 km, the pressure is 350.0 mm of Hg, and the temperature is
-23°C. What is the volume of the balloon at this altitude?

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.