HESI A2 Physics

Correct Answer: A

Rationale: The correct answer is A because laminar flow is characterized by smooth, parallel layers of fluid particles moving in a uniform manner without mixing. This flow pattern occurs at low Reynolds numbers, where viscous forces dominate over inertial forces. Option B is incorrect as it describes turbulent flow, which is characterized by erratic and chaotic motion. Option C is incorrect because high viscosity would lead to more laminar flow, not hinder it. Option D is incorrect as incompressibility is a property of fluids and does not specifically characterize laminar flow.

Correct Answer: D

Rationale: During an isothermal expansion, the temperature remains constant, so the internal energy of the gas remains the same. As the gas expands, it does work on the surroundings. Work done is given by W = -PΔV, where P is pressure and ΔV is change in volume. Since the gas is doing work on the surroundings, the work done is positive. The work done is greater than the change in internal energy because some of the work is used to overcome the external pressure to expand and only a portion contributes to the change in internal energy. Therefore, choice D is correct. Choices A and C are incorrect because the work done is not equal to the change in internal energy. Choice B is incorrect because work is being done during the expansion.

Correct Answer: C

Rationale: Step 1: Energy consumption is typically measured in kilowatt-hours. Step 2: Power (in watts) is the rate at which energy is used. Step 3: Energy = Power x Time, as energy consumed is the product of power and time. Step 4: Therefore, the correct expression is Energy = Power x Time (Choice C). Summary: - Choice A is incorrect because power is the rate of energy consumption, not the total energy used. - Choice B is incorrect as it incorrectly combines time and energy without considering the power. - Choice D is incorrect as it rearranges the formula incorrectly, dividing energy by power instead of multiplying.

Correct Answer: A

Rationale: In an adiabatic process, there is no heat transfer between the system and the surroundings (choice A is correct). This is because adiabatic processes occur without any heat exchange, so the heat transfer (Q) is zero. The other choices are incorrect because in an adiabatic process, there is no requirement for constant temperature (choice B), constant pressure (choice C), or no change in internal energy (choice D). Adiabatic processes focus on the absence of heat transfer, not necessarily on the maintenance of specific temperature, pressure, or energy conditions.

Correct Answer: A

Rationale: The correct answer is A: Pressure. Pumps increase fluid pressure by adding energy to the fluid. When the fluid flows through the pump, it gains kinetic energy which is then converted into pressure energy. Choice B is incorrect because pumps do not primarily aim to increase velocity only. Choice C is incorrect as while pumps do increase both pressure and velocity, the primary goal is to increase pressure. Choice D is incorrect as pumps are specifically designed to increase either pressure, velocity, or both, depending on the application.