Nursing Elites

1. An object with a charge of 4 μC is placed 1 meter from another object with a charge of 2 μC. What is the magnitude of the resulting force between the objects?

• A. 0.04 N
• B. 0.072 N
• C. 80 N
• D. 8 × 10−6 N

Correct answer: A

Rationale: To find the magnitude of the resulting force between two charges, we can use Coulomb's law, which states that the force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. The formula for Coulomb's law is: F = k × (|q1 × q2| / r²), where F is the force, k is the Coulomb constant, q1 and q2 are the charges, and r is the distance between the charges. Substituting the given values into the formula: F = (9 × 10⁹ N·m²/C²) × ((4 × 10⁻⁶ C) × (2 × 10⁻⁶ C) / (1 m)²) = 0.04 N. Therefore, the magnitude of the resulting force between the objects is 0.04 N.

2. 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.

3. Jon walks all the way around a rectangular park that is 1 km × 2 km. Which statement is true about Jon’s walk?

• A. The displacement of his walk is 3 kilometers, and the distance traveled is 0 kilometers.
• B. The displacement of his walk is 0 kilometers, and the distance traveled is 16 kilometers.
• C. The displacement of his walk is 6 kilometers, and the distance traveled is 0 kilometers.
• D. The displacement of his walk is 0 kilometers, and the distance traveled is 6 kilometers.

Correct answer: D

Rationale: Jon walks all the way around a rectangular park that is 1 km × 2 km, which means he walks a total distance of 6 kilometers (1 km + 2 km + 1 km + 2 km = 6 km). However, the displacement of his walk is 0 kilometers because he starts and ends at the same point after completing the rectangular path around the park. Displacement refers to the change in position from the starting point to the ending point, regardless of the actual distance traveled. Choice A is incorrect because the total distance traveled by Jon is 6 kilometers, not 0 kilometers. Choice B is incorrect as the displacement is not 0 kilometers, and the distance traveled is 6 kilometers, not 16 kilometers. Choice C is incorrect because the displacement is 0 kilometers, and the distance traveled is 6 kilometers, not 0 kilometers.

4. An electromagnet is holding a 1,500-kg car at a height of 25 m above the ground. The magnet then experiences a power outage, and the car falls to the ground. Which of the following is false?

• A. The car had a potential energy of 367.5 kJ.
• B. 367.5 kJ of potential energy is converted to kinetic energy.
• C. The car retains potential energy of 367.5 kJ when it hits the ground.
• D. The car’s potential energy converts to kinetic energy and then to sound energy.

Correct answer: C

Rationale: When the car falls to the ground, its potential energy is converted to kinetic energy as it accelerates downwards. Upon impact with the ground, the car's kinetic energy is dissipated in various forms, such as sound energy, heat, and deformation energy. Therefore, the car does not retain its initial potential energy of 367.5 kJ when it hits the ground. Choice A is true because the potential energy of the car can be calculated as mgh = 1500 kg * 9.8 m/s^2 * 25 m = 367,500 J = 367.5 kJ. Choice B is true because as the car falls, its potential energy is converted to kinetic energy. Choice D is true as the kinetic energy is eventually dissipated into other forms upon impact.

5. As the frequency of a sound wave increases, what else is true?

• A. Its wavelength decreases.
• B. Its wavelength increases.
• C. Its amplitude decreases.
• D. Its amplitude increases.

Correct answer: A

Rationale: The correct answer is A: 'Its wavelength decreases.' The frequency and wavelength of a sound wave are inversely proportional. As the frequency of a sound wave increases (more oscillations per second), its wavelength decreases. This relationship is described by the formula: Speed of Sound = Frequency x Wavelength. Therefore, to maintain the speed of sound constant, when the frequency increases, the wavelength must decrease. Choices B, C, and D are incorrect because an increase in frequency does not lead to an increase in wavelength or changes in amplitude.

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