HESI A2 Physics

Correct Answer: A

Rationale: The correct answer is A: Pressure. Pumps increase fluid pressure by adding energy to the fluid. When the fluid flows through the pump, it gains kinetic energy which is then converted into pressure energy. Choice B is incorrect because pumps do not primarily aim to increase velocity only. Choice C is incorrect as while pumps do increase both pressure and velocity, the primary goal is to increase pressure. Choice D is incorrect as pumps are specifically designed to increase either pressure, velocity, or both, depending on the application.

Correct Answer: B

Rationale: To find the frequency, we use the formula: speed = wavelength x frequency. Given speed = 12 m/s and wavelength = 2 m, we can rearrange the formula to solve for frequency: frequency = speed / wavelength = 12 m/s / 2 m = 6 Hz. Choice A (38.4 Hz) is incorrect as it would be the frequency if the wavelength was 0.3125 m, not 2 m. Choice C (4.6 Hz) and D (3.75 Hz) are also incorrect as they do not match the calculated frequency of 6 Hz based on the given values.

Correct Answer: A

Rationale: The correct answer is A: 5 miles per hour due southwest. A vector quantity has both magnitude and direction, which is represented by the speed (5 miles per hour) and the direction (southwest). This choice clearly indicates both aspects. Explanation for why the other choices are incorrect: - B: 5 miles per hour: This choice only provides the magnitude of the quantity (speed) without indicating any direction. - C: 5 miles: This choice only provides the magnitude (distance) without any indication of direction. - D: None of the above: This choice dismisses all options without providing the correct representation of a vector quantity with both magnitude and direction.

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: The correct answer is C (24 units). When you double the mass of both objects, the gravitational force between them increases by a factor of 4 (2 times 2). Therefore, the new force of attraction would be 12 units x 4 = 24 units. Choice A (3 units) and B (6 units) are incorrect because they do not account for the increase in mass. Choice D (48 units) is incorrect as it overestimates the effect of doubling the mass on the gravitational force.