by 62 in. The average gauge pressure from the water is 6 psi. What is the total outward force on the window? F = PA = 3) A small statue is recovered in an archaeological dig. Its weight is measured to be 39.3 lb and its volume 0.06 ft 3 . (a) What is the statue's weight density? D w = W/V (b) What substance is it, most likely? Table 4.4 in text. 4) A certain part of an aircraft engine has a volume of 1.7 ft 3 . (a) Find the weight of the piece when it is made of lead. Table 4.4 and D w = W/V; Solve for W = D w V (b) If the same piece is made of aluminum, what is its weight? Table 4.4 and D w = W/V; Solve for W = ρ V (c) Determine how much weight is saved by using aluminum instead of lead. Δ W = W lead - W alum 5)The depth of the Pacific Ocean in the Mariana Trench is 36,198 ft. What is the gauge pressure at this depth? From text p149, p = (0.447 psi/ft)saltwater·h 6) A storage tank 21 m high is filled with gasoline. (Assume the tank is open and exposed to the atmosphere at the top.) (a) Find the gauge pressure at the bottom of the tank. From Table 4.4 and p = Dgh (units are Pa)
5 (b) Calculate the magnitude of the net force that acts on a square access hatch at the bottom of the tank that measures 0.4 m by 0.4 m F = pA 7) A modern-day zeppelin holds 9,780 m 3 of helium. Compute its maximum payload at sea level. (Assume the helium and air to be at 0°C and 1 atm.) Net force = (1.29 kg/m 3 - .18 kg/m 3 )(9.8 m/s 2 )(9780 m 3 ) 8) A juniper-wood plank measuring 0.44 ft by 1 ft by 19 ft is totally submerged in water. (a) What is its weight? W = D w V (b) What is the buoyant force acting on it? F b = D water V (c) What is the size and the direction of the net force on it? F net = F b – W up 9) A rectangular block of ice with dimensions 2 m by 2 m by 0.2 m floats on water. A person weighing 960 N wants to stand on the ice. Would the ice sink below the surface of the water? F net = F b – W ice – W person 10)The wing of an airplane has an average cross-sectional area of 13 m2and experiences a lift force of 96,000 N. What is the average difference in the air pressure (in N/m2) between the top and bottom of the wing? 11)Describe the four phases of matter. Compare their external, observable properties. 12)Why is it that a person can lay still on a "bed" of nails without suffering any serious injuries but would incur severe puncture wounds to his feet if he tried to stand barefoot on the same "bed"? 13) (a) Would the weight density of water be different on the Moon than it is on Earth? (b) What about the mass density? 14) The pressure in the air along the upper surface of an aircraft's wing (in flight) is lower than the pressure along the lower surface. Compare the speed of the air flowing over the wing to that of the air flowing under the wing.
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