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Correct Answer: D
Correct Answer: D
Method / Topic: Physics
The correct option matches the required rule and the given information.
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Correct Answer: D
Method / Topic: Physics
Continuity requires Q = Av to remain constant. Halving the radius reduces cross-sectional area πr² to one-fourth, so velocity must increase by a factor of four. This result follows from conservation of volume for steady incompressible flow. This result follows from the stated physical model and consistent SI units. For MCAT physics, first identify the system, list known quantities, and choose the governing relationship before substituting numbers. Track direction, signs, exponents, and unit conversions; then test whether the magnitude is physically reasonable. Common distractors omit a round trip, confuse radius with area, ignore an inverse-square or fourth-power dependence, use peak instead of average behavior, or mix stored energy with dissipated power. In clinical and laboratory settings, the same
helps interpret imaging depth, fluid flow, electrical discharge, forces, and energy safely. A final dimensional check should reproduce the unit requested in the
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PASSAGE 2 — BLOOD FLOW MODEL A researcher models blood as an incompressible fluid flowing steadily through a horizontal artery. A section of radius 2.0 mm narrows to radius 1.0 mm. The volume flow rate is 4.0 × 10⁻⁶ m³/s. For a separate calculation, assume laminar flow obeys Poiseuille's law, Q = ΔPπr⁴/(8ηL). Blood density is 1000 kg/m³. QUESTION 4: What happens to the average blood speed as the artery radius decreases from 2.0 mm to 1.0 mm?
Explanation
Correct Answer: D
Method / Topic: Physics
The correct option matches the required rule and the given information.
Short Explanation
Detailed Explanation
Correct Answer: D
Method / Topic: Physics
Continuity requires Q = Av to remain constant. Halving the radius reduces cross-sectional area πr² to one-fourth, so velocity must increase by a factor of four. This result follows from conservation of volume for steady incompressible flow. This result follows from the stated physical model and consistent SI units. For MCAT physics, first identify the system, list known quantities, and choose the governing relationship before substituting numbers. Track direction, signs, exponents, and unit conversions; then test whether the magnitude is physically reasonable. Common distractors omit a round trip, confuse radius with area, ignore an inverse-square or fourth-power dependence, use peak instead of average behavior, or mix stored energy with dissipated power. In clinical and laboratory settings, the same
helps interpret imaging depth, fluid flow, electrical discharge, forces, and energy safely. A final dimensional check should reproduce the unit requested in the
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