Exercícios Resolvidos - Hidrostática | Parte 2

Solved Exercises 7) A U-shaped tube, with a uniform cross-sectional area of ​​1 cm², contains water (ρA = 10³ kg/m³) in static equilibrium. What is the volume of oil (ρO = 800 kg/m³), in cubic centimeters, that must be placed in one of the branches of the tube to cause a difference of 2 cm between the upper surfaces of the oil and the water, as shown in the figure? a) 10 cm³ b) 20 cm³ c) 30 cm³ d) 40 cm³ e) 50 cm³ 8) Using the device in the figure, it is intended to raise a car with a mass of 1.0 10³ kg to a height of 3.0 m relative to its initial position. To do this, the force F⃗_1 indicated is applied to piston 1, and the car rises very slowly, in uniform motion. The areas of pistons 1 and 2 are, respectively, 2.0 m² and 10 m². At the location, g = 10 m/s². Neglecting the action of gravity on the pistons and on the oil, as well as friction and the compressibility of the oil, what is the magnitude of F⃗_1? a) 1.0 x 10³ N b) 2.0 x 10³ N c) 3.0 x 10³ N d) 4.0 x 10³ N e) 5.0 x 10³ N 9) An object floats in water with half of its volume submerged, as shown in the figure. Regarding this experiment, it can be stated that: a) the buoyant force of the water on the object has a magnitude equal to half the weight of the object. b) the volume of water displaced by the object is equal to the volume of the object. c) the mass of the displaced water is equal to half the mass of the object. d) the weight of the displaced water has an intensity equal to the weight of the object. e) the buoyant force has an intensity equal to half the weight of the displaced water. 10) From a platform with a crane, a cylindrical concrete block is slowly lowered into the water at a constant speed. Figure I shows the block, still outside the water, at time t1, and Figure II shows the same block at a later time t2, when it is already inside the water. Choose the alternative whose graph BEST represents the tension in the crane cable as a function of time.