To determine air velocity changes, it is proposed to measure the electric current required to maintain a platinum wire of \(0.25-\mathrm{mm}\) diameter at a constant temperature of \(77^{\circ} \mathrm{C}\) in a stream of air at \(27^{\circ} \mathrm{C}\).

(a) Assuming Reynolds numbers in the range \(40

(b) Calculate the current required when the air velocity is \(15 \mathrm{~m} / \mathrm{s}\) and the electrical resistivity of the platinum wire is \(17.1 \times 10^{-5} \Omega \cdot \mathrm{m}\).