Nursing Elites

1. What characterizes laminar flow?

• A. Smooth, parallel layers of fluid particles
• B. Erratic and turbulent motion of fluid particles
• C. High viscosity hindering flow
• D. Incompressibility of the fluid

Correct answer: A

Rationale: Laminar flow is characterized by the smooth, parallel movement of fluid particles along layers in a predictable manner. This flow regime occurs at low velocities and is in contrast to turbulent flow, where fluid particles exhibit erratic and chaotic motion. The viscosity of the fluid does not hinder laminar flow; instead, it influences the resistance to flow. Incompressibility is a property of fluids but does not specifically define laminar flow. Therefore, the correct answer is A as it accurately describes the behavior of fluid particles in laminar flow, making B, C, and D incorrect.

2. Psychrometrics is a branch of thermodynamics that deals with the properties of:

• A. Ideal gases.
• B. Magnetic materials.
• C. Mixtures of moist air and water vapor.
• D. Nuclear reactions.

Correct answer: C

Rationale: Psychrometrics is the study of the physical and thermodynamic properties of gas-vapor mixtures, especially mixtures of moist air and water vapor. This branch of thermodynamics focuses on the relationships between temperature, pressure, humidity, and other properties of these mixtures. Choice A, ideal gases, is incorrect because psychrometrics specifically deals with gas-vapor mixtures, not ideal gases. Choice B, magnetic materials, and Choice D, nuclear reactions, are unrelated to psychrometrics and thermodynamics, making them incorrect. Understanding psychrometrics is crucial in fields like heating, ventilation, air conditioning, and refrigeration (HVAC&R) to design systems that effectively control air quality, comfort, and temperature.

3. If a wave has a frequency of 60 hertz, which of the following is true?

• A. It completes one cycle per minute.
• B. It measures 60 m from crest to crest.
• C. It completes 60 cycles per second.
• D. It measures 60 m from crest to trough.

Correct answer: C

Rationale: The frequency of a wave is the number of cycles it completes in one second. A wave with a frequency of 60 hertz completes 60 cycles per second. Therefore, choice C is correct. Choice A is incorrect because a frequency of 60 hertz means 60 cycles per second, not per minute. Choice B is incorrect as the frequency of the wave does not determine the distance from crest to crest. Choice D is also incorrect as the frequency does not relate to the distance from crest to trough.

4. What is the net force acting on the car?

• A. 450 N
• B. 700 N
• C. 1,500 N
• D. 6,300 N

Correct answer: C

Rationale: To determine the net force acting on an object, we need to consider the sum of the forces acting in the same direction and subtract the forces acting in the opposite direction. In this scenario, there is a force of 4,200 N to the right and a force of 2,700 N to the left. By subtracting the leftward force from the rightward force (4,200 N - 2,700 N), we find that the net force acting on the car is 1,500 N to the right. Therefore, choice C, 1,500 N, is the correct answer. Choice A, 450 N, is too small as it does not account for the total forces involved. Choice B, 700 N, is also incorrect as it is not the result of the correct mathematical operation on the given forces. Choice D, 6,300 N, is too large and does not align with the calculation based on the forces provided.

5. 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.

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