Nursing Elites

1. A car is moving in a circle at a constant speed. Which of the following is NOT true about its motion?

• A. It has a constant centripetal acceleration
• B. Its tangential velocity remains constant
• C. It experiences a force directed towards the center of the circle
• D. It covers the same distance in equal time intervals along its circular path

Correct answer: B

Rationale: In circular motion at a constant speed, the car has a constant centripetal acceleration (choice A), experiences a force directed towards the center of the circle (choice C), and covers the same distance in equal time intervals along its circular path (choice D). However, the tangential velocity of an object in circular motion at a constant speed changes continuously as it moves around the circle, so it is not constant (choice B). The change in tangential velocity allows the car to maintain its motion in a circular path despite moving at a constant speed. Choice A is incorrect because centripetal acceleration is indeed present to keep the car moving in a circular path. Choice C is incorrect as a force towards the center is required to keep the car in circular motion. Choice D is incorrect because the car covers equal distances in equal time intervals to maintain its circular trajectory.

2. When baking soda (sodium bicarbonate) reacts with vinegar (acetic acid), what type of reaction occurs?

• A. Combustion
• B. Double displacement
• C. Decomposition
• D. Synthesis

Correct answer: B

Rationale: When baking soda (sodium bicarbonate) reacts with vinegar (acetic acid), a double displacement reaction occurs. In this reaction, the positive ions in baking soda switch places with the positive ions in vinegar to form water, carbon dioxide, and a salt. Combustion involves a reaction with oxygen to produce heat and light energy. Decomposition is the breakdown of a compound into simpler substances, which is not the case in the given reaction. Synthesis is the combination of substances to form a more complex compound, which is also not the type of reaction observed when baking soda and vinegar react.

3. What principle explains the relationship between pressure, volume, and temperature for ideal gases?

• A. Law of conservation of energy
• B. Newton's laws of motion
• C. Ideal gas law
• D. Archimedes' principle

Correct answer: C

Rationale: The correct answer is the Ideal Gas Law (Choice C). The ideal gas law, PV = nRT, describes the relationship between pressure (P), volume (V), temperature (T), and the number of moles of gas (n) for an ideal gas. It states that the product of pressure and volume is directly proportional to the absolute temperature of the gas when the number of moles is held constant. This law is a fundamental principle in understanding the behavior of ideal gases. Choices A, B, and D are incorrect. The Law of conservation of energy (Choice A) pertains to the principle that energy cannot be created or destroyed; Newton's laws of motion (Choice B) describe the relationship between the motion of an object and the forces acting on it; Archimedes' principle (Choice D) deals with the buoyant force exerted on an object immersed in a fluid. These principles are not directly related to the relationship between pressure, volume, and temperature for ideal gases.

4. Find the lowest coefficients that will balance the following combustion equation: __C H + __O2 → __CO2 + __H2O

• A. 1:5:5:2
• B. 4:10:20:8
• C. 2:9:10:4
• D. 2:5:10:4

Correct answer: C

Rationale: To balance the combustion equation CxHy + O2 → xCO2 + y/2 H2O, we need to balance the carbon and hydrogen atoms. The balanced equation for the given combustion is: 2C H4 + 9O2 → 2CO2 + 4H2O. This means that the correct coefficients are 2:9:10:4, which corresponds to choice C. Choice A (1:5:5:2) does not balance the equation correctly, choice B (4:10:20:8) has excessive oxygen and does not balance the equation, and choice D (2:5:10:4) does not provide the correct ratio of oxygen to balance the equation.

5. How do vaccines stimulate the immune system to develop memory without causing full-blown illness? What type of molecule in a vaccine typically triggers the immune response?

• A. Toxins produced by the pathogen
• B. Live, attenuated (weakened) forms of the pathogen
• C. Inactivated (dead) forms of the pathogen
• D. Antigens (specific molecules) from the pathogen

Correct answer: D

Rationale: Vaccines work by triggering the immune system to develop memory without causing illness. They typically contain antigens, which are specific molecules from the pathogen. These antigens stimulate the immune system to produce a targeted immune response without causing full-blown sickness. By presenting these antigens, vaccines help the immune system create memory cells that remember the pathogen. This memory allows the immune system to respond more effectively if it encounters the pathogen in the future. Choices A, B, and C are incorrect because vaccines do not typically contain toxins, live pathogens, or inactivated forms of the pathogen. Instead, vaccines primarily rely on specific molecules (antigens) to induce an immune response.

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