A blimp is filled with 400 m of helium. How big a payload can the balloon lift? (The density of air is 1.29 kg/m'; the density of helium is 0.18 kg/m.) (444 kg) An ideal fluid flows through a pipe made of two sections with diameters of 1.0 and 3.0 inches, respectively. The speed of the fluid flow through the 3.0-inch section will be what factor times that through the 1.0-inch section? (1/9) An ideal fluid, of density 0.90 x 10 kg/m', flows at 6.0 m/s through a level pipe with radius of 0.50 cm. The pressure in the fluid is 1.3 x 10" N/m . This pipe connects to a second level pipe, with radius of 1.5 cm. Find the speed of flow in the second pipe. (0.67 m/s) Water flows at 15 m/'s through a pipe with radius 0.040 m. The pipe goes up to the second floor of the building, 3.0 m higher, and the pressure remains unchanged. What is the speed of the water flow in the pipe on the second floor? (13 m/s) A 15 000-N car on a hydraulic lift rests on a cylinder with a piston of radius 0.20 m. If a connecting cylinder with a piston of 0.040-m radius is driven by compressed air, what force must be applied to this smaller piston in order to lift the car? (600 N)A copper wire of length 2.0 m, cross sectional area 7.1 x 10m and Young's modulus 1 1 x 1010 N/m has a 200-kg load hung on it. What is its increase in length? (5.0 mm) A uniform pressure of 7.0 x 10" N/mis applied to all six sides of a copper cube. What is the percentage change in volume of the cube? (for copper, B = 14 x 10 0N/m?) (0.5 x 10-3%) Consider two steel rods, A and B. B has three times the area and twice the length of A, so Young's modulus for B will be what factor times Young's modulus for A? (1.0) How large a force is necessary to stretch a 2.0-mm-diameter steel wire (Y = 2.0 x 10" N/m?) by 1.0%? (6.3 x 103 N) What is the total force on the bottom of a 2.0-m-diameter by 1.0-m-deep round wading pool due to the weight of the air and the weight of the water? (1 atmosphere = 1.0 x 10 N/m) (3.4 x 10# N)