Welcome to your Density and Pressure(Senior Class Physics Study by Topics) NAME EMAIL PHONE NUMBER 1. Calculate the pressure on Radeyah's thumb when she exerts a force of 20N and the top of the pin is square, the length of each side being 10mm0.2N/mm² 2N/mm² 20N/mm² 12N/mm² 0.2N/mm² 2. An open tank holds water 1.25m deep. If a small hole of cross-sectional area 3cm² is made at the bottom of the tank, calculate the mass of water per second initially flowing at the hole (g = 10m/s², density of water = 1000kg/m³) 1.5kg/s 4.5kg/s 3kg/s 5.5kg/s 3. In an experiment using the relative density bottle, the following results were recorded.Mass of an empty bottle + stopper = 50gMass of a bottle full of water + stopper = 80gMass of bottle full of liquid Q + stopper = 74gUse these results to calculate the relative density of liquid Q 0.60 1.25 1.60 0.80 0.93 4. The pressure exerted by a liquid in a container is dependent on the density of the liquid volume of the liquid mass of the liquid cross-sectional area of the container 5. Mechanical pumps cannot compress gases in a container move fluids in a vertical direction increase the atmospheric pressure decrease the pressure in an enclosure move fluids in a horizontal direction 6. A mercury barometer, with a tube of uniform diameter and length of 850mm above the mercury level in the reservoir, reads 750mm on a day when the atmospheric pressure is 760mmHg. What will be the atmospheric pressure on a day when it reads 730mm. 738.3mm 765.8mm 100mm 130mm 7. What volume of alcohol with a density of 8.4 x 10²kg/m³ would have the same mass as 4.2m³ of petrol whose density is 7.2 x 10²kg/m³? 5.8m³ 3.6m³ 4.9m³ 5.0m³ 1.4m³ 8. The opposing force which one layer of liquid exerts on another is called occlusion dynamic force viscosity limiting force 9. Which of the following statements is/are true?I. detergents poured into water increases its surface tension.II. oil poured onto water reduces its surface tension.III. surface tension helps to keep the eggs of water insects aloft. I only II only I & II only III only II & III only 10. By which of the following processes does a piece of blotting paper absorbs a drop of ink from a sheet of writing paper? the capillarity rise of the ink into the blotting paper fibres the action of the forces of cohesion between the blotting paper fibres and the ink the action of the forces of cohesion between the molecules of the blotting paper fibres the diffusion of the ink into the blotting paper fibres the action of the force of viscousity between the molecules of the ink 11. A body whose mass is 2kg has a volume of 500cm³ just floats when completely immersed in a liquid. Calculate the density of the liquid 4000kg/m³ 1000000kg/m³ 400kg/m³ 1000kg/m³ 12. 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 tube I, II, III & IV I & III Only I, III & IV Only I, II & III Only 13. Mercury is a better barometric fluid than water becauseI. it needs no colouringII. its density is many times greater than that of waterIII. it does not wet glassIV. it has a high boiling point. I, II & III I & II only III & IV only II only 14. An object weighs 22kg in water and 30kg in air. What is the upthrust exerted by the liquid on the object? (g = 10m/s²) 220N 520N 50N 80N 15. Which of the following cannot be correctly explained using the concept of surface tension? formation of soap bubbles formation of spherical droplets when water drips from a tap crawling of insects on the surface of a pond floating of balloon in the air 16. A hydrometer is an instrument for measuring the relative density of a liquid by finding the apparent loss in weight depth of water in a vessel atmospheric pressure when the air is humid relative density of a liquid by the method of floatation relative humidity of the air 17. Which of the following statements is correct?The reading of pressure on a mercury barometer is dependent on the temperature of mercury the atmospheric pressure the cross-sectional area of the tube acceleration due to gravity the density of mercury 18. It is observed that water will wet a clean glass because the cohesion of water to glass is weaker than the cohesion of water molecules adhesion of water molecules is weaker than the cohesion of water to glass adhesion of water molecules is stronger than the cohesion of water molecules cohesion of water to glass is stronger than the cohesion of water molecules 19. Two capillary tubes of the same bore are dipped into water and mercury respectively. The water level rises in one tube while the mercury level falls in the other. This is because the cohesive force of water is equal to the adhesive force between water and glass the molecules of mercury have stronger bonding than those of water the adhesive force between mercury and glass is greater than the cohesive force of mercury the adhesive force between water and glass is greater than the cohesive force of water mercury is denser than water 20. A ship floating in clear water of density 1000kg/m³ moves to sea water of density 1050kg/m³ where it floats again. The upthrust on the ship then? increases by 0.05 times decreases increases stays constant decreases by 0.05 times 21. A rectangular tank contains water to the depth of 2m. If the base is 4m x 3m, calculate the force on the base ( density of water = 1000kg/m³, g = 10m/s²) 1,700N 20,000N 24,000N 240,000N 22. If a spherical metal bob of radius 3cm is fully immersed in a cylinder containing water and the water level rises by 1cm. What is the radius of the cylinder? 12cm 6cm 3cm 1cm 23. The stylus of a phonograph record exerts a force of 4 x 10-2N/m2 on a groove of radius 10-2m. Compute the pressure exerted by the stylus on the groove. 1.27N/m² 12.73N/m² 127.32N/m² 1,273N/m² 24. 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. 0.360N 0.24N 0.6N O.18N 25. In which of the following is surface tension important? the floating of balloon in air the floating of a ship in water the diffusion of sugar solution across a membrane the floating of dry needle in water 1 out of 25 Time is Up! Time's up