Use the thermal-diffusivity value estimated from the above problem to find out whether any part of a fruit of diameter \(8 \mathrm{~cm}\) hanging in a tree will freeze if the ambient temperature suddenly drops to \(-6{ }^{\circ} \mathrm{C}\), from an initial temperature of \(15^{\circ} \mathrm{C}\). The heat transfer coefficient to the fruit surface is estimated as \(10 \mathrm{~W} / \mathrm{m}^{2} \cdot \mathrm{K}\). This is, of course, a function of the air velocity.