Nursing Elites

1. What happens to the work done on an object when the angle between the force and displacement is 90 degrees?

• A. Maximum work is done
• B. No work is done
• C. Minimum work is done
• D. Work is infinite

Correct answer: B

Rationale: When the angle between the force and displacement is 90 degrees, the work done is given by the formula W = F * d * cos(theta), where theta is the angle between the force and displacement vectors. Since cos(90 degrees) = 0, the work done becomes zero. This means that no work is done on the object when the angle between the force and displacement is 90 degrees. Choice A is incorrect because maximum work is done when the force and displacement are in the same direction (theta = 0 degrees). Choice C is incorrect as minimum work is done when the force and displacement are parallel (theta = 0 degrees), not perpendicular. Choice D is incorrect because work cannot be infinite; it depends on the force, displacement, and the cosine of the angle between them.

2. Which vitamin plays a vital role in immune function?

• A. Vitamin A
• B. Vitamin B12
• C. Vitamin D
• D. Vitamin E

Correct answer: C

Rationale: Vitamin D is the correct answer. It plays a vital role in immune function by regulating the immune system and enhancing the pathogen-fighting effects of monocytes and macrophages. Deficiency in Vitamin D has been linked to increased susceptibility to infections and autoimmune diseases, highlighting its importance in maintaining a healthy immune response. Vitamin A (Choice A) is essential for vision and skin health but is not primarily known for its role in immune function. Vitamin B12 (Choice B) is important for red blood cell formation and neurological function, not specifically immune function. Vitamin E (Choice D) acts as an antioxidant and is beneficial for skin health and cell function, but it is not primarily associated with immune system support.

3. What is the primary function of tight junctions, specialized regions between animal cells?

• A. Communication between cells
• B. Anchorage between cells
• C. Selective passage of materials
• D. All of the above

Correct answer: C

Rationale: The correct answer is C: Selective passage of materials. Tight junctions act as specialized structures between animal cells that create a barrier to the passage of materials. Their primary function is to prevent the leakage of extracellular fluid and control the selective passage of molecules between cells. This selective control is crucial in regulating the movement of substances across cell layers. Tight junctions do not directly facilitate communication between cells or provide anchorage between cells, as their main role is to regulate the passage of materials. Choices A and B are incorrect as tight junctions do not primarily serve for communication or anchorage between cells.

4. What is the SI unit of measurement for work?

• A. Newton-meter (N·m)
• B. Joule (J)
• C. Watt (W)
• D. Meter per second (m/s)

Correct answer: B

Rationale: The correct answer is B: Joule (J). Work is defined as the amount of energy transferred by a force acting through a distance. The Joule is the unit used to measure this energy transfer. Choice A, Newton-meter (N·m), is the unit for torque, not work. Choice C, Watt (W), is the unit of power, not work. Choice D, Meter per second (m/s), is a unit for speed or velocity and is not related to work.

5. Which of the following is an example of a chemical property of matter?

• A. Boiling point
• B. Flammability
• C. Density
• D. Conductivity

Correct answer: B

Rationale: Flammability is an example of a chemical property of matter because it describes how a substance reacts with oxygen in the air to produce heat and light. Chemical properties involve the ability of a substance to undergo a chemical change or reaction, such as burning. Boiling point, density, and conductivity are examples of physical properties, not chemical properties. Boiling point is the temperature at which a substance changes from a liquid to a gas, density is the mass of a substance per unit volume, and conductivity is the ability to conduct electricity. Therefore, flammability best exemplifies a chemical property as it pertains to the substance's reaction with oxygen, while the other options are physical properties that describe characteristics without changing the substance's chemical composition.

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