Nursing Elites

1. Which of the following describes a vector quantity?

• A. 5 miles per hour due southwest
• B. 5 miles per hour
• C. 5 miles
• D. None of the above

Correct answer: A

Rationale: A vector quantity is characterized by both magnitude and direction. In the provided options, choice A, '5 miles per hour due southwest,' fits this definition as it includes both the magnitude (5 miles per hour) and the direction (southwest), making it a vector quantity. Choices B and C only provide the magnitude without indicating any direction, hence they do not represent vector quantities.

2. Capillarity describes the tendency of fluids to rise or fall in narrow tubes. This phenomenon arises from the interplay of:

• A. Buoyancy and pressure differentials
• B. Density variations and compressibility of the fluid
• C. Viscous dissipation and inertial effects
• D. Surface tension at the liquid-gas interface and intermolecular forces

Correct answer: D

Rationale: Capillarity occurs due to surface tension and intermolecular forces between the liquid and the walls of the narrow tube. These forces cause the liquid to rise or fall depending on the cohesion and adhesion properties. Surface tension at the liquid-gas interface and intermolecular forces are responsible for capillary action, making choice D the correct answer. Choices A, B, and C are incorrect as they do not directly relate to the specific forces involved in capillarity.

3. Enthalpy (H) is a thermodynamic property defined as the sum of a system's internal energy (U) and the product of its pressure (P) and volume (V). The relationship between these is:

• A. H = U + PV
• B. H = U - PV
• C. H = U / PV
• D. H = PV / U

Correct answer: A

Rationale: Enthalpy (H) is defined as H = U + PV, where U represents internal energy, P is pressure, and V is volume. Enthalpy includes both the internal energy of a system and the energy required to create space for the system against an external pressure. Therefore, the correct relationship between enthalpy, internal energy, pressure, and volume is H = U + PV. Choice B is incorrect as subtracting PV would not account for the work done against pressure. Choice C is incorrect as dividing U by PV doesn't represent the definition of enthalpy. Choice D is incorrect as dividing PV by U is not the correct relationship based on the definition of enthalpy.

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. A spring has a spring constant of 20 N/m. How much force is needed to compress the spring from 40 cm to 30 cm?

• A. 200 N
• B. 80 N
• C. 5 N
• D. 2 N

Correct answer: D

Rationale: The change in length of the spring is 40 cm - 30 cm = 10 cm = 0.10 m. The force required to compress or stretch a spring is given by Hooke's Law: F = k × x, where F is the force, k is the spring constant (20 N/m in this case), and x is the change in length (0.10 m). Substituting the values into the formula: F = 20 N/m × 0.10 m = 2 N. Therefore, the correct answer is 2 N. Choice A (200 N) is incorrect because it miscalculates the force. Choice B (80 N) is incorrect as it does not apply Hooke's Law correctly. Choice C (5 N) is incorrect as it underestimates the force required.

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