HESI A2 Physics Quizlet

Correct Answer: B

Rationale: The correct answer is B, the highest peak. At the highest peak, the car has the greatest height above the ground, resulting in the greatest potential energy due to gravity. Potential energy is directly proportional to the height of an object above the reference point. As the car descends from the peak, potential energy is converted to kinetic energy. Choices A, C, and D are incorrect because potential energy is not solely determined by the start or end of the ride, nor the lowest point on the roller coaster.

Correct Answer: B

Rationale: To find the object distance, we can use the mirror formula: 1/f = 1/di + 1/do. Given f=2 cm, di=6 cm, we can solve for do. Plugging in the values, we get 1/2 = 1/6 + 1/do. Solving for do, we get do=6 cm. Therefore, the correct answer is B (6 cm). Choice A (3 cm) is incorrect because it does not satisfy the mirror formula equation. Choice C (12 cm) and D (30 cm) are also incorrect as they do not correspond to the calculated object distance of 6 cm.

Correct Answer: A

Rationale: As the frequency of a sound wave increases, its wavelength decreases because the speed of sound remains constant in a given medium. This is described by the formula speed = frequency x wavelength. Therefore, when frequency increases, wavelength must decrease to maintain a constant speed. Summary: Choice A is correct because frequency and wavelength are inversely proportional. Choices B, C, and D are incorrect as they do not follow the relationship between frequency and wavelength in a sound wave.

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: The correct answer is C: Boundary layer effect. The boundary layer is the thin layer of fluid that adheres to a solid surface in fluid flow. This occurs due to viscosity, which causes the fluid particles to stick to the surface. This layer affects the overall flow behavior and drag force on the object. Buoyancy (A) is the upward force exerted on an object submerged in a fluid. Bernoulli's principle (B) relates to the conservation of energy in fluid flow. Surface tension minimization (D) pertains to minimizing the surface area of a liquid to reduce its surface tension, not relevant to the adherence of fluid to a solid surface in flow.