A piece of aluminum weighing 6 kg and initially at a temperature of 300◦C is suddenly immersed in a fluid at 20◦C. The convection heat-transfer coefficient is 58W/m2 · ◦C.Taking the aluminum as a...

A piece of aluminum weighing 6 kg and initially at a temperature of 300◦C is
suddenly immersed in a fluid at 20◦C. The convection heat-transfer coefficient is
58W/m2 · ◦C.Taking the aluminum as a sphere having the same weight as that given,
estimate the time required to cool the aluminum to 90◦C, using the lumped-capacity
method of analysis.