Tiêu đề 10. MECHANICAL PROPERTIES OF FLUIDS.pdf ✅

(1) 3 (2) 2 (3) 2.4 (4) 1.8 17. Two similar wires under the same load yield elongation of and respec‐ tively. If the area of cross-section of the first wire is then the area of cross section of the second wire is (1) (2) (3) (4) 18. Assertion : Water flows faster than honey. Reason : The coefficient of viscosity of water is less than honey. (1) Both Assertion and Reason are cor- rect and Reason is the correct explana- tion of the Assertion. (2) Both Assertion and Reason are cor- rect but Reason is not the correct explana- tion of the Assertion. (3) Assertion is cor- rect but Reason is incorrect. (4) Assertion is incor- rect but reason is correct. 19. The level of water in a tank is high. A hole of area is made at the bottom of the tank. The rate of leakage of water from the hole is (1) (2) (3) (4) 20. A balloon has volume of . It is filled with hydrogen . If the density of air is , it can lift a total weight of (1) (2) (3) (4) 21. Assertion : The path taken by a fluid particle under a steady flow is a streamline. Reason : The flow of fluid is said to be steady if at any given point, the quantity of fluid flowing per sec‐ ond through any section remains constant. (1) Both Assertion and Reason are cor- rect and Reason is the correct explana- tion of the Assertion. (2) Both Assertion and Reason are cor- rect but Reason is not the correct explana- tion of the Assertion. (3) Assertion is cor- rect but Reason is incorrect. (4) Assertion is incor- rect but reason is correct. 22. A metal bar of length and area of cross sec‐ tion A is clamped between two rigid supports. For the material of the rod, its Young's modulus is Y and coefficient of linear expansion is . If the the temperature of the rod increased by , the force exerted by the rod on the sup‐ ports is (1) (2) (3) (4) 23. Identify the incorrect statement. (1) Bulk modulus is relevant for solids, liq- uids and gases (2) Young's modulus and shear modulus are relevant only for solids. (3) Shear modulus for liquids is infinity (4) Metals have large values of Young's modulus than elastomers 24. A disc of paper of radius has a hole of radius . It is floating on a liquid of surface tension . The force of surface tension on the disc is (1) (2) (3) (4) 25. A marble of mass and diameter is gently released in a tall cylinder containing honey. If the marble displaces mass of the liquid, then the terminal velocity is proportional to (1) (2) (3) (4) 26. Along a streamline (1) The velocity of fluid particle remains constant (2) The velocity of all fluid particle crossing a given position is constant (3) The velocity of all fluid particle at a given instant is constant (4) The speed of a fluid particle remains constant 27. Surface tension of a soap bubble is . Work done to increase the ra‐ dius of soap bubble from to will be Take (1) (2) (3) (4) 1.0 mm 0.05 mm 4 mm2 8 mm2 6 mm2 12 mm2 10 mm2 5 m 1 cm2 (g = 10 m/s 2) 10 −3 m3/s 10 −4 m3/s 10 m3/s 10 −2 m3/s 1000 m3 (ρ = 0.09 g/L) 1.29 g/L 600 kg 1200 kg 300 kg 1800 kg L α Δt ∘ C Y A α Δt Y ALΔt Y ∝ AL Δt Y LαΔt A R r T T.3πR T.4π(R + r) T.2π(R + r) T.2π(R − r) x 2r y(< x) (x − y) (x + y) (x − y) r x + y r 2.0 × 10 −2Nm−1 3.5 cm 7 cm [π = ] 22 7 0.72 × 10 −4 J 18.48 × 10 −4 J 9.24 × 10 −4 J 5.76 × 10 −4 J