HESI A2 Physics Practice Test

Correct Answer: C

Rationale: The gravitational force between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them (F = G * (m1 * m2) / r^2). When the distance is halved, the force quadruples (2^2 = 4 times). Therefore, if the original force is 12 units, when the distance is halved, the new force will be 12 * 4 = 48 units. Therefore, the correct answer is C. Choice A (3 units) is incorrect because the force increases when the distance is halved. Choice B (6 units) is incorrect as well, as the force should increase more when the distance is halved. Choice D (48 units) is incorrect because the new force of attraction is not doubled but quadrupled when the distance is halved.

Correct Answer: A

Rationale: Coulomb's law relates to electrostatic interaction. It describes the force between two charged objects based on their charges and the distance between them. It is mathematically represented as F = k*q1*q2/r^2, where F is the force, k is the Coulomb constant, q1 and q2 are the charges, and r is the distance between the charges. This law is fundamental in understanding and calculating the behavior of electrically charged particles. Summary: B: Rigid body motion - unrelated to Coulomb's law. C: Heat conduction - unrelated to Coulomb's law. D: Universal gravitation - Coulomb's law is specific to electric charges, not gravitational forces.

Correct Answer: C

Rationale: To calculate kinetic energy, we use the formula KE = 0.5 * mass * velocity^2. Plugging in the values (0.5 * 500 kg * (10 m/s)^2), we get 0.5 * 500 * 100 = 25000 J. Therefore, the correct answer is C (2.5 * 10^4 J). Choice A (50 J) is incorrect as it is too low. Choice B (250 J) is incorrect, as it only considers the mass without accounting for the velocity. Choice D (5.0 * 10^5 J) is incorrect as it overestimates the kinetic energy due to incorrect calculations.

Correct Answer: A

Rationale: The correct answer is A: 0 watts. When an appliance draws 0 amperes, it means no current flows, so no power is consumed. Power (in watts) is calculated as Voltage x Current. Since the current is 0, the power consumed is 0 watts. Choice B, C, and D are incorrect because they assume there is power consumption when there is no current flowing.

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.