HESI A2 Physics

Correct Answer: D

Rationale: To find the total voltage in a series circuit, you add the voltages of each battery. In this case, with four 5 V batteries connected in series, the total voltage would be 5 V + 5 V + 5 V + 5 V = 20 V. Therefore, the correct answer is D. Choice A (5.0 V) is incorrect because that would be the voltage of just one battery, not the total voltage of the circuit. Choice B (10.0 V) is incorrect as well since it represents the total voltage of two batteries, not four. Choice C (15.0 V) is also incorrect as it would be the total voltage of three batteries, not four.

Correct Answer: B

Rationale: The correct answer is B: F_b = W_d, the weight of the fluid displaced by the object. This is because the buoyant force acting on an object submerged in a fluid is equal to the weight of the fluid displaced by the object, as stated by Archimedes' principle. When an object is submerged, it displaces a volume of fluid equal to its own volume. The weight of this displaced fluid exerts an upward force on the object, which is the buoyant force. Choices A, C, and D are incorrect because the buoyant force is not equal to the object's weight, the density of the fluid, or the object's volume. The correct answer is based on the principle of fluid displacement and buoyancy.

Correct Answer: B

Rationale: The continuity equation in fluid dynamics states that the mass entering a system must equal the mass exiting the system for mass to be conserved. This is why the correct answer is B: Mass. Momentum (A) is related to the motion of fluids, not mass conservation. Energy (C) is related to the total energy of the system, not specifically mass conservation. Angular momentum (D) is related to rotational motion, not mass conservation. Therefore, the correct answer is B.

Correct Answer: C

Rationale: The correct answer is C: Hydrogen gas. This is because gases are highly affected by changes in temperature due to their particles having more kinetic energy. When temperature increases, gas particles move faster, increasing pressure. Conversely, when temperature decreases, gas particles move slower, decreasing pressure. In contrast, liquid nitrogen (choice A) and salt crystals (choice B) are not as affected by temperature changes due to their stable structures. Iron filings (choice D) are also not significantly affected by temperature changes as they are solid and have a fixed shape and volume.

Correct Answer: A

Rationale: Surface tension is caused by the cohesive forces between molecules in a fluid, which are the intermolecular forces. These forces create an imbalance at the surface, resulting in the phenomenon of surface tension. Gravitational attraction (B) is not the primary cause of surface tension, viscous dissipation (C) is related to fluid flow resistance, and pressure differentials (D) within the fluid do not directly cause surface tension. Therefore, the correct answer is A.