Nursing Elites

1. When two identical charged spheres, both positively charged, are brought close together, the electrostatic force between them will be:

• A. Slightly attractive
• B. Zero
• C. Strongly attractive
• D. Strongly repulsive

Correct answer: D

Rationale: When two positively charged spheres are brought close together, they will experience a repulsive force due to their like charges. The electrostatic force causes the spheres to repel each other, making the correct answer D: Strongly repulsive. The force is not dependent on the material of the spheres, and the force is definitely not zero, as like charges repel. Choice A is incorrect as like charges do not attract each other. Choice C is incorrect as like charges repel, not attract.

2. A box is moved by a 15 N force over a distance of 3 m. What is the amount of work that has been done?

• A. 5 W
• B. 5 N⋅m
• C. 45 W
• D. 45 N⋅m

Correct answer: D

Rationale: Work done is calculated using the formula: Work = Force x Distance. In this case, the force applied is 15 N and the distance covered is 3 m. Thus, work done = 15 N x 3 m = 45 N⋅m. Therefore, the correct answer is 45 N⋅m. Choice A (5 W) is incorrect because work is measured in joules (J) or newton-meters (N⋅m), not in watts (W). Choice B (5 N⋅m) is incorrect as it miscalculates the work by not multiplying the force by the distance. Choice C (45 W) is incorrect because work is not measured in watts (W) but in newton-meters (N⋅m).

3. 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.

4. As a car is traveling on the highway, its speed drops from 60 mph to 30 mph. What happens to its kinetic energy?

• A. Its energy is halved.
• B. Its energy is doubled.
• C. Its energy is quadrupled.
• D. Its energy is divided by four.

Correct answer: A

Rationale: The correct answer is A. Kinetic energy is proportional to the square of the velocity. When the speed drops from 60 mph to 30 mph, the kinetic energy is halved. Choice B is incorrect because halving the speed results in halving the kinetic energy, not doubling it. Choice C is incorrect because quadrupling the kinetic energy would require increasing the speed fourfold, not halving it. Choice D is incorrect because dividing the energy by four would imply a different relationship between speed and kinetic energy, which is not the case.

5. A system undergoes an isobaric process (constant pressure). In this process, the work done (W) by the system is:

• A. Zero, if the volume change (ΔV) is zero.
• B. Positive and equal to the pressure multiplied by the volume change (W = PΔV).
• C. Negative and equal to the pressure multiplied by the volume change.
• D. Independent of the pressure or volume change.

Correct answer: B

Rationale: In an isobaric process (constant pressure), the work done is given by the formula W = PΔV, where P is the pressure and ΔV is the change in volume. If the volume does not change, the work done is zero, not negative. Choice A is incorrect as it states the work done is zero when the volume change is zero, which is the correct condition for zero work. Choice C is incorrect as it incorrectly suggests that the work done is negative in an isobaric process. Choice D is incorrect as the work done in an isobaric process is indeed dependent on the volume change and pressure.

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