HESI A2 Physics Quizlet

Correct Answer: B

Rationale: To find the diameter of a circle, you simply multiply the radius by 2. In this case, the radius is 6 meters, so the diameter would be 6 x 2 = 12 meters. Therefore, the correct answer is B (12 m). Choice A (6 m) is the same as the given radius, not the diameter. Choices C (18 m) and D (36 m) are incorrect as they are multiples of the radius, not the diameter. The key is to remember that the diameter is always double the radius in a circle.

Correct Answer: A

Rationale: To calculate density, divide the mass by the volume. In this case, 24 g / 6 cm3 = 4 g/cm3. This is the correct answer (A) because density is expressed in units of mass per volume. Choice B is incorrect as it has the inverse units. Choices C and D are incorrect as they do not match the calculated value based on the given mass and volume.

Correct Answer: B

Rationale: The correct answer is B: The speed of light. In Einstein's mass-energy equation (E=mc^2), 'c' represents the speed of light in a vacuum, which is approximately 3 x 10^8 meters per second. This constant is crucial in the equation as it shows the relationship between mass and energy. The speed of light is a fundamental physical constant and plays a significant role in various aspects of physics, including relativity. Incorrect choices: A: Distance in centimeters - Distance in centimeters is not represented by 'c' in Einstein's equation. C: Degrees Celsius - 'c' does not represent temperature in degrees Celsius in the equation. D: Centrifugal force - 'c' does not represent centrifugal force in the equation.

Correct Answer: B

Rationale: The Reynolds number (Re) is used to characterize the flow regime of a fluid, determining if it is laminar or turbulent. It is calculated as the ratio of inertial forces to viscous forces. For low Re, flow is laminar, while for high Re, flow is turbulent. Surface tension (C) and buoyancy force (D) do not directly relate to Re. Fluid density (A) affects the Reynolds number indirectly through viscosity.

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.