The helium-filled balloon shown in Fig P9.81 is to be used as a wind-speed indicator. The specific weight of the helium is \(y=0.011 \mathrm{lb} / \mathrm{ft}^{3}\), the weight of the balloon material is \(0.20 \mathrm{lb}\), and the weight of the anchoring cable is negligible. Plot a graph of \(\theta\) as a function of \(U\) for \(1 \leq U \leq 50 \mathrm{mph}\). Would this be an effective device over the range of \(U\) indicated? Explain.

Figure P9.81

Transcribed Image Text:

U 2-ft diameter