HESI A2 Physics Quizlet

Correct Answer: A

Rationale: To find the object's velocity, we use the formula for momentum: momentum = mass x velocity. Given momentum = 180 kg⋅m/s and mass = 45 kg, we rearrange the formula to solve for velocity: velocity = momentum / mass. Substituting the values, velocity = 180 kg⋅m/s / 45 kg = 4 m/s. Therefore, the correct answer is A: 4 m/s. Summary: B: 8.1 km/s and C: 17.4 km/h are incorrect as they do not match the calculated velocity of 4 m/s. D: 135 m/s is incorrect as it is significantly higher than the calculated velocity of 4 m/s.

Correct Answer: B

Rationale: Rationale: Viscosity is the resistance of a fluid to flow. It determines how easily a fluid can flow and is crucial in various applications like fluid dynamics. In contrast, inertia (choice A) is related to the mass of an object, not a property of a fluid. Compressibility (choice C) refers to the change in volume of a fluid under pressure, not its resistance to flow. Buoyancy generation (choice D) is related to the upward force exerted on an object immersed in a fluid, not a property of the fluid itself. Therefore, the correct answer is B as it directly relates to the definition and significance of viscosity.

Correct Answer: A

Rationale: The correct answer is A because a refrigerator operates on a Carnot cycle, which involves removing heat from a cold reservoir at a lower temperature. This aligns with the basic principle of how refrigerators work, by transferring heat from inside the refrigerator to the outside environment. Choice B is incorrect because refrigerators do not create cold; they simply transfer heat. Choice C is incorrect because refrigerators actually decrease the total entropy in the system by cooling the inside of the refrigerator. Choice D is incorrect as refrigerators do not operate isothermally at both the hot and cold reservoirs; there is a temperature difference between the two reservoirs to allow for heat transfer.

Correct Answer: D

Rationale: The correct answer is D: ∫ dQ/T ≤ 0. This is based on the Clausius inequality which states that for a cyclic process involving heat transfer at a constant temperature T, the integral of dQ/T must be less than or equal to zero. This inequality arises from the second law of thermodynamics, specifically stating that heat cannot spontaneously flow from a colder body to a hotter body. If the integral were greater than zero, it would imply a violation of this principle. The other choices are incorrect because they do not accurately represent the Clausius inequality or the relationship between heat transfer and temperature in a cyclic process. Choice A is incorrect as there is indeed a relationship between heat transfer and temperature. Choice B is incorrect as it should be ≤ 0, not ≥ 0. Choice C is incorrect as the integral of Q/T should not be constant for a cyclic process.

Correct Answer: D

Rationale: Surface tension is the result of cohesive forces between liquid molecules at the surface, creating a net inward force. When a small object floats on the liquid surface, the surface tension exerts a restoring force towards equilibrium, keeping the object stable. This force pulls the object back towards the liquid surface if it is displaced. This is why choice D, "Restoring force towards equilibrium," is the correct answer. Choices A, B, and C are incorrect. Buoyant force (A) acts on objects immersed in a fluid, not on objects floating on the surface. Pressure difference (B) would not cause sinking of a floating object. Drag force (C) is a resistance force that opposes motion, not related to surface tension in this context.