HESI A2 Physics Practice Test

Correct Answer: A

Rationale: The correct answer is A: Mass. Mass is an intrinsic property of a substance that remains constant regardless of temperature changes. This is because mass is a measure of the amount of matter in an object and does not depend on external factors like temperature. Volume (B) can change with temperature as substances expand or contract. Phase (C) can change with temperature shifts, such as from solid to liquid or gas. Solubility (D) can also be influenced by temperature, as it affects how well a substance dissolves in a solvent. Therefore, mass is the only property that remains constant regardless of temperature variations.

Correct Answer: A

Rationale: To find force, we use the formula Work = Force x Distance. Given Work = 100 N⋅m and Distance = 20 m, we can rearrange the formula to find Force: Force = Work / Distance = 100 N⋅m / 20 m = 5 N. Therefore, the correct answer is A (5 N) because 5 N of force was applied to move the object. Option B (80 N) is incorrect because it does not match the calculated force of 5 N. Option C (120 N) is incorrect because it is not the result of the calculation. Option D (2,000 N) is incorrect because it is significantly higher than the calculated force of 5 N.

Correct Answer: D

Rationale: The surrounding air is NOT considered a part of the system when analyzing a power plant as it acts as the environment outside the system boundary. The system typically includes components directly involved in the energy conversion process, such as the fuel, working fluid, and turbine. The surrounding air, while it may have an impact on the plant's operations, is not a component within the system boundary and does not play a direct role in the energy conversion process. Choices A, B, and C are all integral parts of the power plant system as they are directly involved in the conversion of energy from the fuel to electricity.

Correct Answer: D

Rationale: To calculate momentum, we use the formula: momentum = mass x velocity. Given mass = 5 kg and velocity = 5 m/s, the momentum is 5 kg x 5 m/s = 25 kg⋅m/s. Therefore, choice D (25 kg⋅m/s) is the correct answer. Choice A (10 kg⋅m/s) is incorrect as it doesn't account for both mass and velocity. Choice B (16.2 km/h) is incorrect as it is a unit conversion for speed, not momentum. Choice C (24.75 kg⋅m/s) is incorrect as it doesn't match the calculated momentum value.

Correct Answer: D

Rationale: The correct answer is D. Electrons complete a cycle 60 times per second in a 60 Hz household alternating current. This is because the frequency of AC refers to the number of complete cycles per second. Electrons moving back and forth create the alternating current flow. A: Incorrect. The power rating of a bulb (in watts) is determined by the voltage and current, not the frequency. B: Incorrect. The current in household circuits is typically much lower than 60 amperes for safety reasons. C: Incorrect. Voltage drop is dependent on the resistance in the wire and the current flowing, not the frequency of the current.