HESI A2 Physics Quizlet

Correct Answer: D

Rationale: To compress the spring from 40 cm to 30 cm, we calculate the change in length = 40 cm - 30 cm = 10 cm = 0.1 m. The force needed is given by Hooke's Law: F = k * x, where F is the force, k is the spring constant (20 N/m), and x is the change in length (0.1 m). Therefore, F = 20 N/m * 0.1 m = 2 N. Choice D (2 N) is correct because it correctly applies Hooke's Law. Choices A, B, and C are incorrect because they do not correctly calculate the force based on the given spring constant and change in length.

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: B

Rationale: The strength of a magnetic field is measured in units of Tesla (B), named after Nikola Tesla. Tesla is the unit of magnetic flux density. Amperes (A) measure electric current, Volts (C) measure electric potential, and Coulombs (D) measure electric charge. Magnetic fields are not measured in current, potential, or charge units, making B the correct choice.

Correct Answer: C

Rationale: Step-by-step rationale for why choice C is correct: 1. The first law of thermodynamics is based on the principle of energy conservation. 2. Choice C accurately reflects this principle by stating that energy cannot be created or destroyed, only transferred or transformed. 3. This is in line with the law of conservation of energy, which is a fundamental concept in physics. 4. Choices A, B, and D are incorrect because they do not accurately represent the first law of thermodynamics. 5. Choice A violates the principle of conservation of energy, choice B refers to the second law of thermodynamics, and choice D is not directly related to the first law.

Correct Answer: C

Rationale: To calculate current, we use the formula I = P/V, where P is power in watts and V is voltage in volts. In this case, the power is 780 watts and the voltage is 120 volts. Therefore, I = 780/120 = 6.5 amperes. Choice C is correct. Choice A (660 amperes) is incorrect as it is an unrealistic and excessively high value for current in this scenario. Choice B (150 amperes) is incorrect as it does not align with the calculated value using the formula. Choice D (0.15 amperes) is incorrect as it is the decimal form of the correct answer but not expressed in amperes.