HESI A2 Physics

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.

Correct Answer: D

Rationale: To find amperes, use the formula: Power (W) = Voltage (V) x Current (I) Given: P = 1525W, V = 110V Therefore, I = P / V = 1525W / 110V = 13.8636A ≈ 13.9 amperes (option D). Explanation: The correct answer is D because it correctly calculates the amperes drawn by the hair dryer using the power and voltage values provided. Option A is too high, B and C are too low.

Correct Answer: A

Rationale: To determine the velocity of a wave, you need to use the formula v = fλ, where v is the velocity, f is the frequency, and λ is the wavelength. By multiplying the frequency by the wavelength (option A), you are essentially applying the correct formula for calculating wave velocity. This is because the velocity of a wave is directly proportional to both its frequency and wavelength. Option B (adding the frequency and wavelength) and Option C (subtracting the wavelength from the frequency) do not align with the correct formula for wave velocity calculation, as it involves multiplication rather than addition or subtraction. Option D (dividing the wavelength by the frequency) is also incorrect because the correct operation for determining wave velocity is multiplication, not division.

Correct Answer: C

Rationale: Rationale: 1. A solenoid creates a magnetic field similar to a bar magnet due to its tightly wound coil structure. 2. The field lines inside a solenoid are uniform and parallel, just like a permanent bar magnet. 3. Choice A is incorrect as a straight wire has circular field lines, not parallel like in a solenoid. 4. Choice B is incorrect as a horseshoe magnet has a different field pattern, not parallel like in a solenoid. 5. Choice D is incorrect as a flat sheet conductor does not create a magnetic field similar to a solenoid.

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.