HESI A2 Physics

Correct Answer: D

Rationale: The correct answer is D because salt increases the density of water, making it more buoyant. Higher water density provides greater buoyant force on the boat, allowing it to float more easily. Choices A, B, and C are incorrect as salt does not directly affect the mass of the boat, the volume of water, or the density of the boat itself.

Correct Answer: C

Rationale: Rationale: 1. Speed of sound in a fluid depends on its bulk modulus, which measures the fluid's resistance to compression. 2. Density affects how closely packed the molecules are, influencing the speed of sound propagation. 3. Viscosity and surface tension do not directly affect the speed of sound in a fluid. 4. Choice C is correct as both density and bulk modulus are crucial factors in determining the speed of sound in a compressible fluid.

Correct Answer: B

Rationale: The continuity equation in fluid dynamics states that the mass entering a system must equal the mass exiting the system for mass to be conserved. This is why the correct answer is B: Mass. Momentum (A) is related to the motion of fluids, not mass conservation. Energy (C) is related to the total energy of the system, not specifically mass conservation. Angular momentum (D) is related to rotational motion, not mass conservation. Therefore, the correct answer is B.

Correct Answer: D

Rationale: To calculate impulse, we use the formula Impulse = Change in Momentum. First, calculate the initial momentum: initial momentum = 10 kg * 5 m/s = 50 kg⋅m/s. Then, calculate the final momentum: final momentum = 10 kg * 15 m/s = 150 kg⋅m/s. The change in momentum is final momentum - initial momentum = 150 kg⋅m/s - 50 kg⋅m/s = 100 kg⋅m/s. Therefore, the impulse applied to the object is 100 kg⋅m/s. Choice D is correct as it correctly represents the impulse value. Choices A, B, and C are incorrect as they do not accurately reflect the calculated impulse value.

Correct Answer: D

Rationale: The correct answer is D: Cannot be created or destroyed. According to the law of conservation of energy, energy can neither be created nor destroyed, but only transformed from one form to another. This principle is a fundamental law of physics known as the first law of thermodynamics. Any process involving energy transfer must adhere to this law. Choices A, B, and C are incorrect because they contradict this fundamental principle. Energy cannot be created out of nothing or disappear completely; it can only change forms.