Nursing Elites

1. When a fluid flows past a solid object, a thin layer of fluid adheres to the object's surface due to:

• A. Buoyancy
• B. Bernoulli's principle
• C. Boundary layer effect
• D. Surface tension minimization

Correct answer: C

Rationale: The boundary layer effect occurs when a thin layer of fluid near the surface of a solid adheres to it due to viscosity. This layer experiences a velocity gradient as the fluid farther from the surface moves faster, while the fluid closest to the surface is nearly stationary.

2. An object moves 100 m in 10 s. What is the velocity of the object over this time?

• A. 10 m/s
• B. 90 m/s
• C. 110 m/s
• D. 1,000 m/s

Correct answer: A

Rationale: Velocity is calculated as the displacement divided by the time taken to cover that displacement. In this case, the object moves 100 meters in 10 seconds. Therefore, the velocity is 100 m / 10 s = 10 m/s. Choice B, 90 m/s, is incorrect as it doesn't match the calculated velocity. Choice C, 110 m/s, is incorrect as it is higher than the calculated velocity. Choice D, 1,000 m/s, is incorrect as it is significantly higher than the calculated velocity.

3. Jon walks all the way around a rectangular park that is 1 km × 2 km. Which statement is true about Jon’s walk?

• A. The displacement of his walk is 3 kilometers, and the distance traveled is 0 kilometers.
• B. The displacement of his walk is 0 kilometers, and the distance traveled is 16 kilometers.
• C. The displacement of his walk is 6 kilometers, and the distance traveled is 0 kilometers.
• D. The displacement of his walk is 0 kilometers, and the distance traveled is 6 kilometers.

Correct answer: D

Rationale: Jon walks all the way around a rectangular park that is 1 km × 2 km, which means he walks a total distance of 6 kilometers (1 km + 2 km + 1 km + 2 km = 6 km). However, the displacement of his walk is 0 kilometers because he starts and ends at the same point after completing the rectangular path around the park. Displacement refers to the change in position from the starting point to the ending point, regardless of the actual distance traveled. Choice A is incorrect because the total distance traveled by Jon is 6 kilometers, not 0 kilometers. Choice B is incorrect as the displacement is not 0 kilometers, and the distance traveled is 6 kilometers, not 16 kilometers. Choice C is incorrect because the displacement is 0 kilometers, and the distance traveled is 6 kilometers, not 0 kilometers.

4. Archimedes' principle explains the ability to control buoyancy, allowing:

• A. Objects to sink regardless of density differences.
• B. Airplanes to generate lift for flight.
• C. Submarines to adjust their buoyancy for submergence and resurfacing.
• D. Helium balloons to overcome gravity and float.

Correct answer: C

Rationale: Archimedes' principle states that the upward buoyant force acting on an object submerged in a fluid is equal to the weight of the fluid displaced by the object. Submarines control their buoyancy by adjusting the volume of water they displace, which allows them to submerge and resurface. Choice C is correct because it directly relates to the principle of buoyancy and how submarines utilize it. Choices A, B, and D are incorrect because they do not accurately reflect the application of Archimedes' principle in controlling buoyancy for submergence and resurfacing.

5. A rock has a volume of 6 cm3 and a mass of 24 g. What is its density?

• A. 4 g/cm3
• B. 4 cm3/g
• C. 144 g/cm3
• D. 144 cm3/g

Correct answer: A

Rationale: Density is calculated by dividing the mass of an object by its volume. In this case, the mass of the rock is 24 g and its volume is 6 cm3. By dividing 24 g by 6 cm3, we find that the density of the rock is 4 g/cm3. Choice A is the correct answer because density is expressed in units of mass per unit volume (g/cm3). Choice B is incorrect as it represents the reciprocal of density. Choices C and D are significantly higher values and do not match the calculated density of the rock.

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