HESI A2 Physics

Correct Answer: C

Rationale: The correct answer is C because in a cyclic process, the system returns to its initial state, so the net work done over the entire cycle can be positive, negative, or zero depending on the path taken. If the system undergoes a clockwise cycle on a PV diagram, work is done by the system (positive Wnet). If the cycle is counterclockwise, work is done on the system (negative Wnet). If the cycle is a closed loop, the net work done can be zero. Choices A and B are incorrect because they are too absolute and do not consider the different possibilities in a cyclic process. Choice D is incorrect because the net work done is not necessarily equal to the total heat transferred; it depends on the specific process and path taken.

Correct Answer: B

Rationale: To find the radius of the circular track, we use the formula: circumference = 2 * π * radius. Given circumference = 2,500m, we can rearrange the formula to solve for radius: radius = circumference / (2 * π) = 2,500 / (2 * 3.14) ≈ 398.73m. Therefore, the closest option to the calculated radius is B: 400m. Incorrect answers: A: 1,000m - This is twice the correct radius, not accurate. C: 25m - This is 10 times smaller than the correct radius, not accurate. D: 12m - This is much smaller than the correct radius, not accurate.

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.

Correct Answer: D

Rationale: The correct answer is D. Displacement is the change in position from the starting point to the endpoint, regardless of the path taken. In this case, traveling 500 miles northeast and then 500 miles southwest cancels out the movement, resulting in a displacement of 0 miles. However, the distance traveled is the total distance covered, which is 1,000 miles in this case. Therefore, option D correctly states that the displacement is 0 miles, and the distance traveled is 1,000 miles. Option A is incorrect because the distance traveled is not 0 miles. Option B is incorrect as the displacement is 0 miles. Option C is incorrect as both displacement and distance traveled are not 0 miles.

Correct Answer: B

Rationale: To determine the stretch of the spring when a 30 kg force is applied, we first calculate the spring constant using Hooke's Law: F = kx. Given F1 = 12 kg and x1 = 3 cm, k = F1/x1 = 12 kg / 0.03 m = 400 N/m. Then, for F2 = 30 kg, x2 = F2 / k = 30 kg / 400 N/m = 0.075 m = 7.5 cm. Therefore, choice B (7.5 cm) is the correct answer. Choices A, C, and D are incorrect as they do not align with the calculated value using Hooke's Law.