20. Al and Bob are at opposite ends of a diameter of a silo in the shape of a tall right cireular cylinder with radius 150 ft. Al is due west of Bob. Al begins walking along the edge of the silo at 6 ft per second at the same moment that Bob begins to walk due east at the same speed. The value closest to the time in seconds when Al first can see Bob is: A. 46 В. 47 С. 48 D. 49 E. 50

7. Express the length of (a+b) in terms of 0. 6 FT a -9 F (a+b)=

2. A cylindrical tank contains oil (use density as p in lb/ ft'). The radius of the tank is 3 feet, the length is 12 feet and oil enters and leaves the tank through an opening at the top. The tank is initially full of oil. Use the sketch below and complete each step below to find the work done in pumping all of the oil out of the opening at the top of the tank. You must use the axis provided. No calculators. (a) Find and expression for the volume of a single representative "slab" of oil that will move out of the tank. (b) Find the expression for the distance any single representative "slab" of oil must move to get out of the tank. (c) Find the expression for the force of a single representative "slab" of oil. (d) Set up (BUT DO NOT SOLVE), the Reimann sum that approximates the total work done in pumping all of the oil out of the tank.

16. A pilot is experiencing mechanical difficulties and must land at the nearest airport, either Flyville or Driveton. Which airport is closer, and by how much? Airplane 75.4% Drivet on Fly ville 83.2° 68 km