HESI A2 Physics Quizlet

Correct Answer: A

Rationale: Scalar quantities have only magnitude, no direction. Distance is a scalar because it represents only the magnitude of the measurement, such as "5 meters." Velocity (B) and acceleration (C) are vector quantities because they have both magnitude and direction. Displacement (D) is a vector quantity, as it includes both the distance traveled and the direction of the endpoint from the starting point. Therefore, the correct answer is A (Distance) as it is the only scalar quantity among the choices provided.

Correct Answer: D

Rationale: To find the resistance, we use Ohm's Law: R = V/I. Given V = 120V and I = 25A, we have R = 120V / 25A = 4.8 ohms. Therefore, choice D is correct. Choice A (96 ohms) is incorrect as it does not match the calculated value. Choice B (104 ohms) and choice C (150 ohms) are also incorrect as they do not match the correct resistance value of 4.8 ohms.

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: B

Rationale: The correct answer is B: ṁ = ρvA. This equation is derived from the continuity equation, which states that mass flow rate ṁ remains constant in steady flow. Mass flow rate ṁ is the product of fluid density ρ, cross-sectional area A, and average velocity v. This relationship is crucial for understanding the behavior of fluids in pipes. Choice A is incorrect because the mass flow rate can be determined using the given equation without any additional information. Choice C is incorrect because Bernoulli's principle is not directly related to the calculation of mass flow rate. Choice D is incorrect because the equation of state for the specific fluid is not required to determine the mass flow rate using the continuity equation.

Correct Answer: C

Rationale: To calculate current, we use the formula I = P/V, where P is power in watts and V is voltage in volts. In this case, the power is 780 watts and the voltage is 120 volts. Therefore, I = 780/120 = 6.5 amperes. Choice C is correct. Choice A (660 amperes) is incorrect as it is an unrealistic and excessively high value for current in this scenario. Choice B (150 amperes) is incorrect as it does not align with the calculated value using the formula. Choice D (0.15 amperes) is incorrect as it is the decimal form of the correct answer but not expressed in amperes.