Homework Statement
A metal sphere is subjected to a heat flux, 5000 W/m2. It is originally at 20 C. How long does it take to heat to 90 C?
D = 5 cm
density = 8522 kg/m3
cp = 0.385 kJ/kg-K
k = 104 W/m-k
Homework Equations
rate of heat input = rate of heat accumulation
-k*A*dT/dr = m*cp*dT/dt...