HESI A2 Physics Practice Test

Correct Answer: B

Rationale: To calculate the magnitude of the resulting force, we use Coulomb's Law: \(F = k \cdot \frac{{|q_1 \cdot q_2|}}{{r^2}}\), where \(k\) is the electrostatic constant, \(q_1\) and \(q_2\) are the charges, and \(r\) is the distance between them. Plugging in the values, we get \(F = 9 \times 10^9 \cdot \frac{{3 \times 10^{-6} \cdot 2 \times 10^{-6}}}{{(0.3)^2}} = 0.18\) N. Choice B is correct because it correctly calculates the force using Coulomb's Law. Choices A, C, and D are incorrect because they either miscalculate the force or provide unrealistic values that do not align with the physics of electrostatic forces.

Correct Answer: D

Rationale: The correct answer is D (5 feet). When Jack stands 5 feet away from the mirror, his image will appear the same distance behind the mirror. This is because the distance between Jack and his image in the mirror is equal to the distance between Jack and the mirror itself. Therefore, the image of Jack will also be 5 feet away from him. Choice A (2.5 feet) is incorrect because the image distance is equal to the object distance in a plane mirror. Choice B (3 feet) is incorrect as it does not follow the principle of image formation in a plane mirror. Choice C (4.5 feet) is incorrect as the image distance is always equal to the object distance in a plane mirror.

Correct Answer: B

Rationale: The correct answer is B because fluid dynamics specifically focuses on the motion and behavior of fluids under various conditions. It deals with how fluids move, interact, and change in response to forces. Choice A (Fluid Statics) is incorrect because it pertains to fluids at rest, not in motion. Choice C (Phase transitions) is incorrect as it relates to changes in state, not fluid motion. Choice D (Engineering applications) is too broad, encompassing various aspects beyond just fluid dynamics. Fluid dynamics uniquely studies fluid flow, making choice B the correct option.

Correct Answer: B

Rationale: Step-by-step rationale: 1. Bernoulli's principle states that in a flowing fluid, an increase in flow velocity leads to a decrease in pressure. 2. As the fluid flows faster in a constricted pipe, kinetic energy increases while pressure energy decreases. 3. This relationship between velocity and pressure is consistent for incompressible fluids. 4. Therefore, when the flow velocity increases in a constricted pipe, the pressure will decrease. Summary: - Choice A is incorrect because Bernoulli's principle applies universally to all incompressible fluids. - Choice C is incorrect because pressure changes with velocity according to Bernoulli's principle. - Choice D is incorrect as pressure decreases when velocity increases, as per Bernoulli's principle.

Correct Answer: B

Rationale: The correct answer is B: The ratio of the potential difference between the ends of a conductor to current is a constant, R. This is in accordance with Ohm's law, which states that V (voltage) = I (current) x R (resistance). Ohm's law establishes a direct proportionality between voltage and current when resistance is constant. The constant R represents the resistance of the conductor. Option A is incorrect because voltage and current are directly proportional when resistance is constant, not inversely proportional. Option C is incorrect as voltage is not the amount of charge passing through a point per second, but rather the potential difference. Option D is incorrect as power is calculated using the formula P = VI, not I x V.