HESI A2 Physics Practice Test

Correct Answer: C

Rationale: The correct answer is C (3 ohms) because in a series circuit, the total resistance is the sum of individual resistances. Since the circuit has 3 same-size resistors, each resistor must have the same resistance. Therefore, the total resistance of the circuit is 3 times the resistance of one resistor. Using Ohm's Law (V = IR), with V = 9V and I = 1A, we can find the total resistance (R) as 9V = 1A * R. Thus, R = 9 ohms for the whole circuit. Since each resistor has the same resistance, each resistor must be 1/3 of the total resistance, which is 3 ohms. Choice A (9 ohms) is incorrect because it represents the total resistance of the circuit, not the resistance of each individual resistor. Choice B (6 ohms) is incorrect because it does not consider the equal division of resistance among the three resistors

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: C

Rationale: The correct answer is C: Joule (J). The SI unit for quantifying the transfer of energy due to an applied force is the Joule. This is because energy is measured in Joules, which represent the work done when a force of one Newton is applied over a distance of one meter. Newton (A) is the unit for force, meter per second (B) is the unit for velocity, and kilogram (D) is the unit for mass, not for energy transfer. Therefore, the Joule is the appropriate unit for quantifying energy transfer in this context.

Correct Answer: C

Rationale: The correct answer is C (3 ohms) because in a series circuit, the total resistance is the sum of individual resistances. Since the circuit has 3 same-size resistors, each resistor must have the same resistance. Therefore, the total resistance of the circuit is 3 times the resistance of one resistor. Using Ohm's Law (V = IR), with V = 9V and I = 1A, we can find the total resistance (R) as 9V = 1A * R. Thus, R = 9 ohms for the whole circuit. Since each resistor has the same resistance, each resistor must be 1/3 of the total resistance, which is 3 ohms. Choice A (9 ohms) is incorrect because it represents the total resistance of the circuit, not the resistance of each individual resistor. Choice B (6 ohms) is incorrect because it does not consider the equal division of resistance among the three resistors

Correct Answer: B

Rationale: The correct answer is B: Interface between the liquid and a surrounding gas. This is because in open-channel flow, the free surface is the boundary between the liquid flowing in the channel and the air above it. This interface is essential in determining the behavior of the flow, such as wave formation and surface tension effects. A: The interface between the liquid and the container walls is not the free surface in open-channel flow. C: The bottom of the channel is not the free surface, as the free surface specifically refers to the top boundary of the flowing liquid. D: The region of highest velocity within the liquid is not the free surface, as the free surface is a boundary between the liquid and the surrounding gas, not a velocity-related property.