HESI A2 Physics Quizlet

Correct Answer: A

Rationale: The correct answer is A, P = ρgh. This is derived from the hydrostatic equation, which states that pressure in a static fluid at a depth h is directly proportional to the density of the fluid (ρ), gravitational acceleration (g), and depth (h). Therefore, P = ρgh is the correct formula to calculate pressure in a static fluid. Choice B, P = γh, does not include the density of the fluid and is incorrect. Choice C, P = μgh, introduces a new variable μ which is not part of the hydrostatic equation and is thus incorrect. Choice D, P = bh, does not include the density of the fluid or gravitational acceleration, making it an incorrect formula for calculating pressure in a static fluid.

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: D

Rationale: Surface tension is the result of cohesive forces between liquid molecules at the surface, creating a net inward force. When a small object floats on the liquid surface, the surface tension exerts a restoring force towards equilibrium, keeping the object stable. This force pulls the object back towards the liquid surface if it is displaced. This is why choice D, "Restoring force towards equilibrium," is the correct answer. Choices A, B, and C are incorrect. Buoyant force (A) acts on objects immersed in a fluid, not on objects floating on the surface. Pressure difference (B) would not cause sinking of a floating object. Drag force (C) is a resistance force that opposes motion, not related to surface tension in this context.

Correct Answer: A

Rationale: The correct answer is A because a refrigerator operates on a Carnot cycle, which involves removing heat from a cold reservoir at a lower temperature. This aligns with the basic principle of how refrigerators work, by transferring heat from inside the refrigerator to the outside environment. Choice B is incorrect because refrigerators do not create cold; they simply transfer heat. Choice C is incorrect because refrigerators actually decrease the total entropy in the system by cooling the inside of the refrigerator. Choice D is incorrect as refrigerators do not operate isothermally at both the hot and cold reservoirs; there is a temperature difference between the two reservoirs to allow for heat transfer.

Correct Answer: A

Rationale: The correct answer is A because density is calculated by dividing mass by volume. For block A, density = 6.5g/16.25cm3 = 0.4 g/cm3. To determine the density of other blocks: B = 80g/32cm3 = 2.5 g/cm3, C = 48g/22cm3 = 2.18 g/cm3, D = 100g/250cm3 = 0.4 g/cm3. Since block A and D have the same density of 0.4 g/cm3, block A is the correct answer. Block B and C have higher densities, so they are incorrect choices.