HESI A2
HESI A2 Physics Questions
Question 1 of 5
How might the energy use of an appliance be expressed?
Correct Answer: C
Rationale: The energy use of an appliance can be expressed using the formula Energy = Power Time. In this formula, Energy represents the amount of electricity consumed by the appliance, Power indicates the rate at which the appliance uses electricity (measured in watts), and Time represents the duration for which the appliance is being used (measured in hours). By multiplying the power rating of the appliance by the time it is in use, one can calculate the total energy consumed. Option C is the correct choice because it accurately represents the relationship between power, time, and energy.
Choices A, B, and D present incorrect representations of the relationship between energy, power, and time, making them wrong answers.
Question 2 of 5
What characterizes laminar flow?
Correct Answer: A
Rationale: Laminar flow is characterized by the smooth, parallel movement of fluid particles along layers in a predictable manner. This flow regime occurs at low velocities and is in contrast to turbulent flow, where fluid particles exhibit erratic and chaotic motion. The viscosity of the fluid does not hinder laminar flow; instead, it influences the resistance to flow. Incompressibility is a property of fluids but does not specifically define laminar flow.
Therefore, the correct answer is A as it accurately describes the behavior of fluid particles in laminar flow, making B, C, and D incorrect.
Question 3 of 5
Two 5-ohm resistors are placed in series and wired into a 100-V power supply. What current flows through this circuit?
Correct Answer: B
Rationale: In a series circuit, the total resistance is the sum of the individual resistances.
Therefore, the total resistance in this circuit is 5 ohms + 5 ohms = 10 ohms. Using Ohm's Law (V = I R), we can find the current (I) by dividing the voltage (V) by the total resistance (R). I = V / R = 100 V / 10 ohms = 10 A.
Choice A (2
A) is incorrect because it does not account for the total resistance of the circuit.
Choice C (20
A) and
Choice D (50
A) are also incorrect as they provide values that are not consistent with the calculations based on the given values in the question.
Question 4 of 5
A box is moved by a 15 N force over a distance of 3 m. What is the amount of work that has been done?
Correct Answer: D
Rationale: Work done is calculated using the formula: Work = Force x Distance. In this case, the force applied is 15 N and the distance covered is 3 m. Thus, work done = 15 N x 3 m = 45 Nâ‹…m.
Therefore, the correct answer is 45 Nâ‹…m.
Choice A (5 W) is incorrect because work is measured in joules (J) or newton-meters (Nâ‹…m), not in watts (W).
Choice B (5 Nâ‹…m) is incorrect as it miscalculates the work by not multiplying the force by the distance.
Choice C (45 W) is incorrect because work is not measured in watts (W) but in newton-meters (Nâ‹…m).
Question 5 of 5
When the heat of a reaction is negative, which statement is true?
Correct Answer: C
Rationale: When the heat of a reaction is negative, it indicates that the reaction releases energy in the form of heat. This means that the products have lower energy levels compared to the reactants. Lower energy levels are associated with greater stability in chemical systems.
Therefore, when the heat of a reaction is negative, the products are more stable due to having less energy than the reactants.
Choice A, stating that the products have less energy and are less stable, is incorrect as lower energy levels imply greater stability.
Choice B, stating that the products have more energy and are more stable, is incorrect as lower energy levels lead to higher stability.
Choice D, stating that the products have more energy and are less stable, is incorrect as lower energy levels are associated with higher stability.