Nursing Elites

1. A 10-kg object moving at 5 m/s has an impulse acted on it causing the velocity to change to 15 m/s. What was the impulse that was applied to the object?

• A. 10 kg⋅m/s
• B. 15 kg⋅m/s
• C. 20 kg⋅m/s
• D. 100 kg⋅m/s

Correct answer: D

Rationale: Impulse is the change in momentum of an object. The initial momentum is calculated as 10 kg × 5 m/s = 50 kg⋅m/s, and the final momentum is 10 kg × 15 m/s = 150 kg⋅m/s. The change in momentum (impulse) is 150 kg⋅m/s - 50 kg⋅m/s = 100 kg⋅m/s. Therefore, the impulse applied to the object is 100 kg⋅m/s. Choices A, B, and C are incorrect because they do not reflect the correct calculation of the impulse based on the change in momentum of the object.

2. 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.

3. The operating principle of a metal detector relies on:

• A. The static presence of a permanent magnet
• B. The electromotive force induced by a changing magnetic field
• C. The high electrical conductivity of most metals
• D. The unique thermal signature of metallic objects

Correct answer: B

Rationale: The correct answer is B. Metal detectors work based on the principle of electromotive force induced by a changing magnetic field. When a metal object comes into contact with the detector's magnetic field, it disrupts the field, inducing a current in the metal that can be detected. This principle allows metal detectors to identify the presence of metallic objects without relying on the static presence of a permanent magnet, the high electrical conductivity of metals, or the thermal signature of the objects. Choice A is incorrect because metal detectors do not rely on a static magnet but on the interaction of metals with a changing magnetic field. Choice C is incorrect because while metals do have high electrical conductivity, this is not the principle underlying metal detectors. Choice D is incorrect because metal detectors do not operate based on the thermal signature of objects, but rather on their interaction with magnetic fields.

4. The first law of thermodynamics is a principle of energy conservation. It states that:

• A. Energy can be created or destroyed.
• B. The total entropy of an isolated system always decreases.
• C. Energy can neither be created nor destroyed, only transferred or transformed.
• D. The temperature of a system is directly proportional to its entropy.

Correct answer: C

Rationale: The first law of thermodynamics states that energy cannot be created or destroyed; it can only be transferred or converted from one form to another, ensuring energy conservation in any system. Choice A is incorrect because it goes against the principle of energy conservation. Choice B is incorrect as it refers to the second law of thermodynamics, which states that the total entropy of an isolated system always increases. Choice D is incorrect because the temperature of a system is not directly proportional to its entropy.

5. The specific heat capacity (c) of a material is the amount of heat transfer (Q) required to raise the temperature (ΔT) of a unit mass (m) of the material by one degree (typically Celsius). The relationship between these quantities is described by the equation:

• A. Q = cΔT
• B. Q = mcΔT
• C. Q = c / mΔT
• D. Q = ΔT / mc

Correct answer: A

Rationale: The correct equation relating heat transfer (Q), mass (m), specific heat capacity (c), and change in temperature (ΔT) is Q = mcΔT. This equation states that the heat transfer is equal to the product of the mass, specific heat capacity, and temperature change. Therefore, the correct answer is B, as it correctly represents this relationship. Choices C and D do not correctly represent the relationship between these quantities and are therefore incorrect.

Similar Questions