Welcome to your Density and Pressure(Senior Class Physics Study by Topics) NAME EMAIL PHONE NUMBER 1. The density of water is 1g/cm³ while that of ice is 0.9g/cm³. Calculate the change in volume when 90g of ice is completely melted.9cm³90cm³0cm³100cm³10cm³2. When someone uses her thumb to push a drawing pin into a block of wood, the pressure on the wood is greater than the pressure on the thumb. Answer True (T) or False (F)3. The water manometer in the diagram below is measuring the pressure of the gas supply. If the specific gravity of mercury is 13.6 and the atmospheric pressure is 70cmHg, what is the total pressure of the gas supply in cm of water?955cm949cm73cm67cm952cm4. A piece of wire gauze can be made to lie on water becausethe water surface has the effect of an elastic thin skinof the cohesive forces between the water and the wire gauze moleculesthe water molecules repel the wire gauze upwardthe wire gauze is less dense than water5. A solid weighs 0.040N in air and 0.025N when fully immersed in a liquid of density 800kg/m³. Calculate the volume of the solid0.00002kg/m³0.000003kg/m³0.0000025kg/m³0.000002kg/m³6. A liquid of mass 1000kg fills a rectangular tank of length 2m. If the tank is 4m high, what is the pressure at the middle of the tank?1,000N/m² 2,000N/m² 1,500N/m² 10,000N/m² 7. 40cm³ of liquid P is mixed with 60cm³ of another liquid Q. If the density of P and Q are 1.00kg/m³ and 1.6kg/m³ respectively, what is the density of the mixture?1.25kg/m³0.05kg/m³1.30kg/m³1.36kg/m³8. As a result of air at the top of a barometer, the height of the mercury column is 73.5cm when it should be 75cm, the volume of the space above the mercury is 8cm³. Calculate the correct barometric height when the barometer reads 74cm and the volume of the space above the mercury is 6cm.74.5cm75.1cm76cm72cm9. A rectangular solid block has length 10cm, breadth 5cm and height 2cm. If its lies on a horizontal surface and has density 100kg/m³, calculate the pressure it exerts on the surface.200N/m²20N/m²2N/m²0.2N/m²10. When a paint brush is removed from clean water, the bristles of the brush are pulled together because oflow density of waterthe mass of the brush bristlessurface tensionthe viscousity of the surroundingthe weight of the brush bristles11. A hydrometer is an instrument for measuring therelative humidity of the airdepth of water in a vesselrelative density of a liquid by the method of floatationatmospheric pressure when the air is humidrelative density of a liquid by finding the apparent loss in weight12. The rise or fall of a liquid in a narrow tube is because of thethe surface tension of the liquidthe friction between the walls of the tube and the liquidthe osmotic pressure of the liquidthe viscousity of the liquid13. A heavy object is suspended from a string and lowered into water so that it is completely submerged. The object appears lighter becauseit experiences an upthrustthe tension in the string neutralizes part of the weightthe pressure is low just below the water surfacethe density of water is less than that of the object14. Which of these statements are true of pressure in liquid?I. pressure acts equally in all directionsII. pressure decreases with depthIII. pressure at the same level of a liquid is the sameIV. pressure is dependent on the cross-section area of the barometer tubeI, III & IV OnlyI, II & III OnlyI, II, III & IVI & III Only15. An empty 60L petrol tank has a mass of 10kg. Its mass when full of fuel of relative density 0.72 is53.2kg43.2kg7.2kg33.2kg16. A known sprinkler has 20 holes of cross-sectional area 0.02cm² and is connected to a hose pipe of cross-sectional area 0f 2.4cm². If the speed of the water in the hose pipe 1.5cm/s, find the speed of the water as it emerges from the holes.1.5m/s30m/s9m/s4m/s17. What is the height of the liquid column in a barometer tube that would support an atmospheric pressure of 102,000N/m² if the density of the liquid is 2,500kg/m³. (g = 10m/s²).0.76m39.23m3.92m0.75m18. A solid of weight 0.6N is totally submerged in oil and water respectively. If the upthrust in oil is 0.21N and the R.D of oil is 0.875, find the upthrust in water.0.6N0.24N0.360NO.18N19. In which of the following is surface tension important?the floating of dry needle in waterthe floating of balloon in airthe diffusion of sugar solution across a membranethe floating of a ship in water20. A hydrometer is placed in water and 6.4cm of its stem is immersed. What is the depth of immersion when it is placed in a liquid of R.D 0.8? (density of water = 1g/cm³)70cm8cm60cm9cm21. The diagram is of a faultless simple mercury barometer. Which of the following is NOT correct?a vacuum exists above the mercury in the tubeif the tube is tilted, the vertical height of the mercury column will changethe height of the column will not be the same if another liquid is used instead of mercuryas the barometer is taken up a mountain, h, decreasesthe atmospheric pressure supports a column of mercury, h22. A steel needle floating on the surface of water sinks when kerosene is added to the water becausekerosene causes an increase in the density of waterkerosene causes an increase in the surface tension of waterkerosene causes a decrease in the density of waterkerosene causes a decrease in the surface tension of watera steel needle is denser than kerosene23. A thin hydrometer floats stationary in water at a temperature of about 20ºc. If the water is gradually cooled to 0ºc, their hydrometer will.rise gradually at first and becomes stationary after some timeoscillate gradually in a vertical plane as long as the cooling continuessink gradually at first and become stationary after some timerise gradually at first then begins to sink slowlyneither rise nor fall but remains at a constant level24. Oil from a bottle flows out more easily after it has been warmed becausecohesion between the oil molecules and those of the bottle is reducedmolecules are given potential energy during warmingfriction between the oil layer is reducedoil molecules force one another outosmotic pressure of the oil is increased25. The pressure at any point in a liquid at rest depends only on thesurface area and the viscousitydepth and the densitymass and the volumequantity and the surface area26 out of 25Time is Up!
