Nursing Elites

1. Which vehicle has the greatest momentum?

• A. A 9,000-kg railroad car traveling at 3 m/s
• B. A 2,000-kg automobile traveling at 24 m/s
• C. A 1,500-kg MINI Coupe traveling at 29 m/s
• D. A 500-kg glider traveling at 89 m/s

Correct answer: D

Rationale: The momentum of an object is calculated by multiplying its mass by its velocity. The momentum formula is p = m × v, where p is momentum, m is mass, and v is velocity. Comparing the momentum of each vehicle: A: 9,000 kg × 3 m/s = 27,000 kg·m/s B: 2,000 kg × 24 m/s = 48,000 kg·m/s C: 1,500 kg × 29 m/s = 43,500 kg·m/s D: 500 kg × 89 m/s = 44,500 kg·m/s. Therefore, the glider (500-kg) traveling at 89 m/s has the greatest momentum of 44,500 kg·m/s, making it the correct choice. Options A, B, and C have lower momentum values compared to option D, proving that the 500-kg glider traveling at 89 m/s has the highest momentum among the given vehicles.

2. The buoyant force, F_b, experienced by an object submerged in a fluid is given by:

• A. F_b = W, the object's weight
• B. F_b = W_d, the weight of the fluid displaced by the object
• C. F_b = ρ, the density of the fluid
• D. F_b = V, the object's volume

Correct answer: B

Rationale: The correct formula for the buoyant force experienced by an object submerged in a fluid is given by Archimedes' principle, which states that the buoyant force is equal to the weight of the fluid displaced by the object. This is represented by the formula F_b = W_d, where W_d is the weight of the fluid displaced by the object. This force acts in the opposite direction to gravity and is responsible for objects floating or sinking in fluids. Choice A is incorrect because the buoyant force is not equal to the object's weight. Choice C is incorrect because the density of the fluid is not directly related to the buoyant force. Choice D is incorrect because the object's volume is not the determining factor for the buoyant force.

3. A rock has a volume of 6 cm3 and a mass of 24 g. What is its density?

• A. 4 g/cm3
• B. 4 cm3/g
• C. 144 g/cm3
• D. 144 cm3/g

Correct answer: A

Rationale: Density is calculated by dividing the mass of an object by its volume. In this case, the mass of the rock is 24 g and its volume is 6 cm3. By dividing 24 g by 6 cm3, we find that the density of the rock is 4 g/cm3. Choice A is the correct answer because density is expressed in units of mass per unit volume (g/cm3). Choice B is incorrect as it represents the reciprocal of density. Choices C and D are significantly higher values and do not match the calculated density of the rock.

4. What is the electric field inside a hollow conductor with a net charge?

• A. Remains constant
• B. Decreases
• C. Zero
• D. Becomes unpredictable

Correct answer: C

Rationale: The correct answer is C: Zero. According to Gauss’s Law, the electric field inside a hollow conductor (a conductor with no charge inside but a net charge on its surface) is zero. The charges reside on the outer surface of the conductor, causing the electric field inside to cancel out. Choices A, B, and D are incorrect because the electric field inside a hollow conductor with a net charge is not constant, does not decrease, and does not become unpredictable; it is zero due to the distribution of charges on its surface.

5. What is the purpose of a switch in a circuit?

• A. To reverse the direction of alternating current
• B. To increase the voltage of the battery or cell
• C. To increase the resistance of wires in the circuit
• D. To allow the circuit to open and close

Correct answer: D

Rationale: The purpose of a switch in a circuit is to allow the circuit to open and close. When the switch is turned on, it provides a complete path for the current to flow through the circuit. When the switch is turned off, it breaks the circuit, stopping the flow of current. This function of opening and closing the circuit using a switch is essential for controlling the flow of electricity in various electrical devices and systems. Choices A, B, and C are incorrect because a switch does not reverse the direction of current, increase voltage, or increase resistance in a circuit; its primary function is to open and close the circuit.

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