Nursing Elites

1. For steady, incompressible flow through a pipe, the mass flow rate (ṁ) is related to the fluid density (ρ), cross-sectional area (A), and average velocity (v) via the continuity equation:

• A. ṁ cannot be determined without additional information
• B. ṁ = ρvA
• C. Bernoulli's principle is solely applicable here
• D. The equation of state for the specific fluid is required

Correct answer: B

Rationale: The continuity equation for steady, incompressible flow states that the mass flow rate is the product of the fluid's density, velocity, and cross-sectional area. Hence, ṁ = ρvA. Choice A is incorrect because the mass flow rate can be determined using the given formula. Choice C is incorrect as Bernoulli's principle does not directly relate to the mass flow rate calculation. Choice D is incorrect as the equation of state is not needed to calculate the mass flow rate in this scenario.

2. A 110-volt hair dryer delivers 1,525 watts of power. How many amperes does it draw?

• A. 167.75 amperes
• B. 1.635 amperes
• C. 1.415 amperes
• D. 13.9 amperes

Correct answer: D

Rationale: To determine the amperes drawn by the hair dryer, we use the formula: Amperes = Watts / Volts. The hair dryer operates at 1,525 watts with 110 volts. Dividing 1,525 watts by 110 volts yields 13.9 amperes. Therefore, the correct answer is 13.9 amperes. Choices A, B, and C are incorrect because they do not result from the correct calculation using the formula.

3. Marilyn is driving to a wedding. She drives 4 miles south before realizing that she left the gift at home. She makes a U-turn, returns home to pick up the gift, and sets out again driving south. This time, she drives 1 mile out of her way to pick up a friend. From there, they continue 5 miles more to the wedding. Which of these statements is true about Marilyn’s trip?

• A. The displacement of her trip is 6 miles, and the distance traveled is 6 miles.
• B. The displacement of her trip is 14 miles, and the distance traveled is 14 miles.
• C. The displacement of her trip is 8 miles, and the distance traveled is 14 miles.
• D. The displacement of her trip is 6 miles, and the distance traveled is 14 miles.

Correct answer: C

Rationale: Marilyn’s displacement is calculated based on her final position relative to the starting point. She drives 1 mile to pick up her friend, then 5 miles more to the wedding, totaling 6 miles after returning to her home. So, the correct displacement is 8 miles south from her starting point (4 miles to the gift + 4 miles return + 1 mile to the friend + 5 miles to the wedding). The total distance traveled is 14 miles (adding all the distances). Choice A is incorrect because it miscalculates the displacement. Choice B is incorrect as it overestimates both the displacement and distance traveled. Choice D is incorrect as it underestimates the displacement.

4. What is the main difference between a reversible and irreversible process in thermodynamics?

• A. Reversible processes involve heat transfer, while irreversible processes do not.
• B. Reversible processes occur instantaneously, while irreversible processes take time.
• C. Reversible processes can be run in both directions with the same outcome, while irreversible processes cannot.
• D. Reversible processes violate the first law of thermodynamics.

Correct answer: C

Rationale: A reversible process is an idealized process that can be reversed without leaving any change in either the system or the surroundings. In contrast, irreversible processes cannot be reversed and often involve entropy production or dissipation. Choice A is incorrect because both reversible and irreversible processes can involve heat transfer. Choice B is incorrect as the speed of a process does not determine its reversibility. Choice D is incorrect because reversible processes do not violate the first law of thermodynamics; they comply with it by maintaining a balance between energy inputs and outputs. Therefore, the correct answer is C, as it accurately captures the main difference between reversible and irreversible processes in thermodynamics.

5. Two objects attract each other with a gravitational force of 12 units. If you double the distance between the objects, what is the new force of attraction between the two?

• A. 3 units
• B. 6 units
• C. 24 units
• D. 48 units

Correct answer: A

Rationale: The gravitational force between two objects is inversely proportional to the square of the distance between them. If the distance is doubled, the force will be reduced to 1/4 of the original force. Therefore, the new force of attraction between the two objects will be 12 units / 4 = 3 units. Choice A is correct because doubling the distance reduces the force to 1/4 of the original value. Choices B, C, and D are incorrect as they do not consider the inverse square relationship between distance and gravitational force.

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