Nursing Elites

1. According to Bernoulli's principle, when the flow velocity (v) of an incompressible fluid increases in a constricted pipe, the pressure (P) will:

• A. Depend on the specific fluid type
• B. Decrease
• C. Remain constant
• D. Increase

Correct answer: B

Rationale: Bernoulli's principle states that in a constricted pipe with increasing flow velocity of an incompressible fluid, the pressure decreases. This is due to the conservation of energy, where the total energy of the fluid (sum of kinetic energy, potential energy, and pressure energy) remains constant along the flow path. As the fluid velocity increases, its kinetic energy increases at the expense of pressure energy, causing a decrease in pressure. Therefore, the correct answer is B. Choices A, C, and D are incorrect. The pressure changes in the system are primarily driven by the fluid velocity and the conservation of energy principle, not by the specific fluid type, which is a constant. The pressure is not constant but decreases with increasing flow velocity due to the energy transformation occurring in the system. Lastly, the pressure does not increase; it decreases as the fluid velocity rises.

2. Jack stands in front of a plane mirror. If he is 5 feet away from the mirror, how far away from Jack is his image?

• A. 2.5 feet
• B. 3 feet
• C. 4.5 feet
• D. 5 feet

Correct answer: D

Rationale: When Jack stands in front of a plane mirror, his image appears the same distance behind the mirror as Jack is in front of it. Therefore, if Jack is 5 feet away from the mirror, his image will also appear 5 feet behind the mirror. The total distance from Jack to his image is the sum of these distances, which equals 10 feet. Choices A, B, and C are incorrect because the image distance is not half of the total distance but the same as the object's distance from the mirror.

3. Two objects attract each other with a gravitational force of 12 units. If you double the mass of both objects, what is the new force of attraction between them?

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

Correct answer: C

Rationale: The gravitational force between two objects is directly proportional to the product of their masses. When you double the masses of both objects, the force of attraction between them increases by a factor of 2 x 2 = 4. Therefore, the new force of attraction between the two objects will be 12 units x 4 = 24 units. Choices A, B, and D are incorrect because doubling the mass results in a quadruple increase in force, not a linear one.

4. A 50-kg box of iron fishing weights is balanced at the edge of a table. Peter gives it a push, and it falls 2 meters to the floor. Which of the following statements is true?

• A. Once the box hits the floor, it loses both its kinetic and potential energy.
• B. The box had kinetic energy only when it was balanced at the edge of the table.
• C. The box had both kinetic and potential energy after it fell.
• D. Once the box hits the floor, it loses all its kinetic energy.

Correct answer: C

Rationale: When the box is balanced at the edge of the table, it has potential energy due to its position above the ground. As Peter gives it a push, and it falls 2 meters to the floor, the box then has both kinetic energy (due to its motion) and potential energy (due to gravity). Therefore, the correct statement is that the box had both kinetic and potential energy after it fell. Option A is incorrect because the box retains its energy forms even after hitting the floor. Option B is incorrect as the box has kinetic energy both before and after falling. Option D is incorrect as the box still possesses kinetic energy even after hitting the floor.

5. The efficiency (η) of a heat engine is defined as the ratio of the net work done (Wnet) by the engine to the heat input (Qh) from the hot reservoir. The relationship is expressed as:

• A. η = Wnet / Qh
• B. η = Qh / Wnet
• C. η = Wnet x Qh
• D. η = (Wnet + Qh) / 2

Correct answer: A

Rationale: The correct formula for efficiency (η) of a heat engine is η = Wnet / Qh. Efficiency is defined as the ratio of the net work done by the engine (Wnet) to the heat input from the hot reservoir (Qh). This formula shows how effectively the engine converts heat into useful work, making choice A the correct answer. Choices B, C, and D present incorrect relationships between efficiency, net work done, and heat input, leading to their incorrectness.

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