HESI A2 Physics Practice Test

Correct Answer: D

Rationale: Failed to generate a rationale after 5 retries.

Correct Answer: A

Rationale: When a dielectric material is inserted between the plates of a charged capacitor, the capacitance will increase. This is because the dielectric reduces the electric field between the plates, which allows for more charge to be stored for a given potential difference. The dielectric polarization enhances the capacitance. The other choices are incorrect because capacitance does not decrease or remain the same when a dielectric is added, and it is not unpredictable as the relationship between capacitance and dielectric constant is well-defined.

Correct Answer: D

Rationale: Step-by-step rationale: 1. In an isothermal process, temperature remains constant. 2. Compressing a gas increases its pressure. 3. Work is done on the gas by the surroundings in compression. 4. As work is done on the gas, its internal energy decreases. Therefore, choice D is correct. Summary: A: Incorrect; Internal energy does not increase when work is done on the gas. B: Incorrect; Internal energy does not decrease when work is done on the gas. C: Incorrect; Work is done by the surroundings on the gas, not vice versa.

Correct Answer: C

Rationale: The correct answer is C: Identical. When the crane hoists a massive object at a constant velocity, the work done is the same as lifting it gradually because work done is the force applied multiplied by the displacement in the direction of the force. Since the velocity is constant, the force applied remains constant, and the displacement is the same whether lifted gradually or at a constant velocity. Therefore, the work done is identical in both scenarios. Summary: A: Less - Incorrect. The work done is not less when hoisting a massive object at a constant velocity. B: More - Incorrect. The work done is not more when hoisting a massive object at a constant velocity. D: Dependent on the object's mass - Incorrect. The object's mass does not affect the work done in this scenario.

Correct Answer: B

Rationale: The correct answer is B: Interface between the liquid and a surrounding gas. This is because in open-channel flow, the free surface is the boundary between the liquid flowing in the channel and the air above it. This interface is essential in determining the behavior of the flow, such as wave formation and surface tension effects. A: The interface between the liquid and the container walls is not the free surface in open-channel flow. C: The bottom of the channel is not the free surface, as the free surface specifically refers to the top boundary of the flowing liquid. D: The region of highest velocity within the liquid is not the free surface, as the free surface is a boundary between the liquid and the surrounding gas, not a velocity-related property.