Pressure

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Q1 A block with flat, rectangular sides rests on a table. The block is now turned so that it rests with its largest side on the table. How do the force and pressure exerted change?
Q2 A farmer has two carts. The carts have the same weight, but one has four narrow wheels and the other has four wide wheels. In rainy weather, which cart sinks less into soft ground and why?
Q3 Which situation is an example of a force acting over a large area to produce a small pressure?
Q4 A drawing pin (thumb tack) has a sharp point and a flat end. The pin is pushed into a wooden board. How do the pressure and the force at the sharp point compare with the pressure and the force at the flat end?
Q5 The diagram shows a glass block resting on a table top. Which expression gives the pressure exerted on the table by the block?
Q5 explanation
Q6 The pressure produced by a cubic block of length l is P. Find the pressure if the cube has a length of 2l instead.

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Q7 The diagram shows three vases each with the same base area. Each vase contains water of the same depth. Which statement about the water pressures at points P, Q and R is correct?
Q8 The diagrams show two swiming pools. One contains fresh water and the other contains saltwater. Salt water is more dense than fresh water. At which labelled point is the pressure the greatest?
Q9 The diagrams show four divers at the bottom of four different swimming pools. Two swimming pools contain fresh water and two contain salt water. Fresh water is less dense than salt water. Which diver feels the least pressure from the water?
Q10 A student places four identical beakers on a bench. Two beakers contain salt water of density 1.1g/ cm3 and two beakers contain pure water of density 1.0g/ cm3. Which beaker exerts the greatest pressure on the bench?
Q11 Four beakers contain the same liquid. At which point is the pressure the greatest?
Q12 The diagrams show liquids in containers. Which column of liquid exerts the greatest pressure on the base of its container?
Q13 The surface of water in a domestic tank is 6 m above a cold water tap. The density of water is 1000 kg m-3. What is the minimum possible pressure of water as it leaves the tap?

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Q14 A tall container which is open to the atmosphere contains a layer of liquid L, floating on liquid M. Liquid M has a density which is twice as great as that of liquid L. Which graph is correct?
Q15 Bubbles of gas, escaping from the mud at the bottom of a deep lake, rise to the surface. As the bubbles rise they get larger. Why is this?
Q16 Water of depth 10m exerts a pressure equal to atmospheric pressure. An air bubble rises to the surface of a lake which is 20m deep. What is the volume of the air bubble at the bottom of the lake?

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Q17 The diagram shows a simple mercury barometer. Which height is used as a measurement of atmospheric pressure?
Q18 The diagram shows a simple mercury barometer. The atmospheric pressure increases. Which distance increases?
Q19 The diagrams below show 4 mercury barometers. In which of these is the external pressure greatest?
Q19 explanation
Q20 The first diagram on the left shows a simple barometer in its original state. The next four diagrams show the barometer after something has been done to it. Which of the following diagrams A, B, C, D is correct?
Q21 The diagram shows a simple mercury barometer inclined at 60° to the horizontal. The atmospheric pressure in cm in Hg is
Q23 The diagram shows a mercury column in a test tube supported by the atmosphere. What is the pressure of the gas given that the atmospheric pressure is 76 cm Hg?
Q22 Some air is trapped in the space above the mercury in a barometer. When the glass tube is pressed down into the mercury bath, which of the following best describes the change of l and h?

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Q24 The diagram shows a manometer containing a liquid. The manometer is used to find the difference between the pressure of a gas and atmospheric pressure. Which distance represents this pressure difference?
Q25 A forked tube contains air in one branch and a vacuum in the other as shown. The pressure of the enclosed air is
Q25 explanation
Q26 The figure below shows a U-tube manometer filled with water and two incompressible liquids P and K. The density of water is 1.0 g cm-3. Note that the figure is not drawn to scale. What can be deduced about the densities of the liquids?
Q27 The diagram shows a simple mercury barometer alongside a mercury manometer. The manometer contains some trapped gas. What is the pressure of the trapped gas?
Q28 The diagram shows a water manometer made form wide glass tubing and is designed to compare the pressure of two gases P & Q. Which of the following statements is true?
Q29 A column of liquid X floats on water in a U-tube of uniform cross-section area. If the density of water is 1000 kgm-3, find the density of liquid X.
Q30 The apparatus in the diagram below is set up at a constant temperature of 20℃, d=12 cm, h=10 cm. Air is trapped inside the left handed closed limb. If the right-hand limb is raised such that h is 15 cm, what is the length of the trapped air, d ?

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Q31 Which is not true of hydraulic machines?
Q32 The system shown in the diagram contains a liquid. A downward force of 80 N is exerted on piston K. What will be the upward force exerted by the liquid on piston L?
Q32 explanation
Q33 In the diagram below a person of mass 50 kg is standing on a platform over the piston of area shown below. What height of water h will just support him?
Q34 The diagram shows the principle of a hydraulic system. The area of the master cylinder is 12.0cm2 and the area of the slave cylinder is 8.0cm2. The force applied to the master piston is 60 N, producing a pressure of 5.0 N/cm2. Which is correct?

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Course Description