Nursing Elites

1. Why are boats more buoyant in salt water than in fresh water?

• A. Salt decreases the mass of the boats.
• B. Salt increases the volume of the water.
• C. Salt affects the density of the boats.
• D. Salt increases the density of the water.

Correct answer: D

Rationale: Salt increases the density of water, making saltwater more buoyant than freshwater. The higher density of saltwater provides more lift to a boat, enabling it to float more easily compared to in freshwater. Choice A is incorrect because salt does not affect the mass of the boats. Choice B is incorrect as salt does not increase the volume of water. Choice C is incorrect since salt affects the density of water, not the boats themselves. Therefore, the correct answer is that salt increases the density of the water, resulting in boats being more buoyant in salt water than in fresh water.

2. The triple point of a substance is the specific temperature and pressure at which all three phases (solid, liquid, and gas) can coexist in thermodynamic equilibrium. Which of the following statements about the triple point is true?

• A. It can vary depending on the container size.
• B. It is a unique point for each pure substance.
• C. The pressure at the triple point can be zero for some substances.
• D. The temperature at the triple point can be above the boiling point of the liquid phase.

Correct answer: B

Rationale: The triple point is a unique temperature and pressure where all three phases (solid, liquid, and gas) of a pure substance can coexist in equilibrium. It is a constant for each substance and independent of container size. Choice A is incorrect because the triple point is a fixed point regardless of the container size. Choice C is incorrect as the pressure at the triple point is specific for each substance and will not be zero unless the substance has unique properties. Choice D is incorrect since the temperature at the triple point is precisely defined and cannot be above the boiling point of the liquid phase.

3. Why doesn’t a raindrop accelerate as it approaches the ground?

• A. Gravity pulls it down at a constant rate.
• B. Air resistance counteracts the gravitational force.
• C. Its mass decreases, decreasing its speed.
• D. Objects in motion decelerate over distance.

Correct answer: B

Rationale: The correct answer is B. As a raindrop falls, it experiences air resistance which counteracts the gravitational force pulling it down. This balancing of forces prevents the raindrop from accelerating further as it approaches the ground. Choice A is incorrect because while gravity is pulling the raindrop down, air resistance opposes this force. Choice C is incorrect as the mass of the raindrop remains constant during its fall. Choice D is incorrect because objects in motion may decelerate due to various factors, but in this case, the focus is on why the raindrop doesn't accelerate.

4. An incandescent lamp consumes 60 Joules of energy per second. What is the power rating of this lamp?

• A. 1 Watt (W)
• B. 60 Watts (W)
• C. 1/60 Joules
• D. Impossible to determine without knowing the voltage

Correct answer: B

Rationale: Power is defined as energy consumed per unit time. If the lamp consumes 60 Joules of energy per second, the power rating is 60 Watts. Therefore, choice B is correct. Choice A ('1 Watt') is incorrect because the lamp consumes 60 Joules per second, not 1 Joule per second. Choice C ('1/60 Joules') is incorrect as it does not represent the power rating. Choice D ('Impossible to determine without knowing the voltage') is incorrect because power can be calculated using energy consumption per unit time without needing to know the voltage.

5. A 1,000-kg car drives at 10 m/s around a circle with a radius of 50 m. What is the centripetal acceleration of the car?

• A. 2 m/s²
• B. 4 m/s²
• C. 5 m/s²
• D. 10 m/s²

Correct answer: A

Rationale: Centripetal acceleration is calculated using the formula a = v² / r, where v = 10 m/s and r = 50 m. Substituting these values: a = (10 m/s)² / 50 m = 100 / 50 = 2 m/s². Therefore, the correct answer is 2 m/s². Choice B, 4 m/s², is incorrect because it is not the result of the correct calculation. Choice C, 5 m/s², is incorrect as it does not match the calculated centripetal acceleration. Choice D, 10 m/s², is incorrect as it does not reflect the correct calculation based on the given values.

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