An aluminum rod 2.5 cm in diameter and 20 cm long protrudes from a wall maintained at 200ºC and is exposed to a convection environment with h = 50W/m2 · ºC and a temperature of 20ºC. Using ∆x = 4 cm write a transient nodal equation for the node at the tip of the fin and determine the maximum allowable time increment for that node.