Nursing Elites

1. 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.

2. 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.

3. According to the zeroth law of thermodynamics, two systems are in thermal equilibrium if:

• A. They have the same pressure.
• B. They have the same volume.
• C. They have the same temperature.
• D. They are made of the same material.

Correct answer: C

Rationale: The correct answer is C: "They have the same temperature." The zeroth law of thermodynamics states that if two systems are each in thermal equilibrium with a third system, they are also in thermal equilibrium with each other. This implies that they have the same temperature. Choice A is incorrect because pressure is not the determining factor for thermal equilibrium. Choice B is incorrect because volume alone does not dictate thermal equilibrium. Choice D is incorrect as the materials the systems are made of do not determine thermal equilibrium according to the zeroth law of thermodynamics.

4. A common example of a shear-thinning (non-Newtonian) fluid is:

• A. Water
• B. Ketchup
• C. Air
• D. Alcohol

Correct answer: B

Rationale: The correct answer is B: Ketchup. Shear-thinning fluids become less viscous under stress. Ketchup is an example of a shear-thinning fluid because its viscosity decreases when it is shaken or squeezed, allowing it to flow more easily. Choice A, Water, is a Newtonian fluid with a constant viscosity regardless of stress. Choice C, Air, is also a Newtonian fluid. Choice D, Alcohol, does not exhibit shear-thinning behavior; it typically has a constant viscosity as well.

5. Bernoulli's principle for an incompressible, inviscid fluid in steady flow states that the mechanical energy, consisting of:

• A. Pressure (P) only, remains constant along a streamline.
• B. Velocity (v) only, remains constant along a streamline.
• C. P + ½ρv² (total mechanical energy), remains constant along a streamline
• D. Density (ρ) only, remains constant along a streamline.

Correct answer: C

Rationale: Bernoulli's principle states that the sum of pressure energy (P), kinetic energy per unit volume (½ρv²), and potential energy per unit volume remains constant along a streamline in an incompressible, inviscid fluid. This means the total mechanical energy of the fluid is conserved, making Choice C the correct answer. Choices A, B, and D are incorrect because Bernoulli's principle involves the conservation of the total mechanical energy, not just pressure, velocity, or density alone.

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