Prob. $3\mathrm{.}6\mathrm{.}87$ p$.$ IP$-43[$Ans: $3000f\frac{t^3}{s}$;$2000f\frac{t^3}{s}$;$2120f\frac{t^3}{s}].$

F FIGURE P$3\mathrm{.}64$

$3\mathrm{.}6\mathrm{.}87$ WP An air cushion vehicle is supported by forcing air into the chamber created by a skirt around the periphery of the vehicle, as shown in Fig. P$3\mathrm{.}6\mathrm{.}87.$ The air escapes through the $3-$in$.$ clearance between the lower end of the skirt and the ground $($or water$).$ Assume the vehicle weighs $10,000lb$ and is essentially rectangular in shape, $3065ft.$ The volume of the chamber is large enough so that the kinetic energy of the air within the chamber is negligible. Determine the flowrate, $Q,$ needed to support the vehicle. If the ground clearance were reduced to $2$ in$.,$ what flowrate would be needed? If the vehicle weight were reduced to $5000lb$ and the ground clearance maintained at $3$ in$.,$ what flowrate would be needed?