When the National Advisory Committee for Aeronautics (NACA)measured the lift and drag on airfoil models in the 1930s & 40sin their specially designed airfoil windtunnel, they made wingsthat spanned the entire section, with the wing tips butted againstthe two side-walls of the tunnel. This was done to ensure that theflow over each airfoil section of the wing was essentiallytwo-dimensional (no wing tip effects). Such an arrangementprevented measuring the lift and drag with a force balance. Instead, using a Pitot tube, the NACA obtained the drag bymeasuring the velocity distribution behind the wing in a planeperpendicular to the plane of the wing, i. e., the Pitot tube, located a fixed distance downstream of the wing, traversed theheight from the top to the bottom of the test section. Using acontrol volume approach, derive a formula for the drag per unitspan on the model as a function of the integral of the measuredvelocity distribution. For simplicity, assume incompressibleflow.

1. the materials manager for a billiard ball maker must periodically place orders for resin, one of the raw materials used in producing billiard balls. she knows that manufacturing uses resin at a rate of 50 kilograms each day, and that it costs $.04 per day to carry a kilogram of resin in inventory. she also knows that the order costs for resin are $100 per order, and that the lead time for delivery is four (4) days.2. at what point should resin be reordered? a. 0 kilograms remainingb. 50 kilograms remainingc. 200 kilograms remainingd. 400 kilograms remaininge. 500 kilograms remaining3. if order size was 1,000 kilograms of resin, what would be the length of an order cycle? a. 0.05 daysb. 4 daysc. 16 daysd. 20 dayse. 50 days4. if the order size was 1,000 kilograms of resin, what would be the average inventory level? a. 50 kilogramsb. 200 kilogramsc. 500 kilogramsd. 800 kilogramse. 1,000 kilograms5. if the order size was 1,000 kilograms of resin, what would be the daily total inventory costs, excluding the cost of the resin? a. $5b. $10c. $20d. $25e. $40