Hot-air ballooning is a popular sport. According to a recent article, "hot-air volumes must be large because air heated to \(150^{\circ} \mathrm{F}\) over ambient lifts only \(0.018 \mathrm{lbf} / \mathrm{ft}^{3}\) compared to 0.066 and 0.071 for helium and hydrogen, respectively." Check these statements for sea-level conditions. Calculate the effect of increasing the hotair maximum temperature to \(250^{\circ} \mathrm{F}\) above ambient.