HESI A2 Physics Practice Test

Correct Answer: C

Rationale: The correct answer is C: 1,500 N. Net force is the sum of all forces acting on an object. In this case, if a car is experiencing a forward force of 2,000 N and a backward force of 500 N, the net force would be 2,000 N - 500 N = 1,500 N acting in the forward direction. Choice A, B, and D are incorrect because they do not consider the direction and magnitude of the forces acting on the car. A and B are too low, while D is too high. By calculating the net force as the vector sum of all forces, we find that the correct answer is C.

Correct Answer: D

Rationale: Cavitation occurs when the pressure drops below the vapor pressure of the fluid, causing bubbles to form and collapse. If the pressure drops below the vapor pressure, the fluid will vaporize, leading to cavitation. Boiling point (A), density (B), and freezing point (C) are not directly related to cavitation. Boiling point is the temperature at which a liquid turns into vapor, density is the mass per unit volume of a substance, and freezing point is the temperature at which a liquid turns into a solid. Only vapor pressure (D) is directly linked to cavitation.

Correct Answer: D

Rationale: The correct answer is D: Refraction. Refraction is the phenomenon of light bending as it passes through different mediums, such as a prism. This occurs due to the change in speed of light when transitioning from one medium to another, causing the light to change direction. Reflection (A) is the bouncing back of light off a surface, not bending. Electrical conduction (B) is the movement of electric charges through a material, not related to light behavior. Diffraction (C) is the bending of light around obstacles or through small openings, not specifically related to prisms.

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: A

Rationale: The correct answer is A: H = U + PV. Enthalpy (H) is defined as H = U + PV, where U is internal energy, P is pressure, and V is volume. This equation comes from the first law of thermodynamics, which states that the change in internal energy of a system is equal to the heat added to the system minus the work done by the system. In this case, the work done by the system is PΔV, which represents the product of pressure and volume. Therefore, the correct relationship between enthalpy, internal energy, pressure, and volume is H = U + PV. Choices B, C, and D are incorrect because they do not accurately represent the definition of enthalpy. Choice B (H = U - PV) is incorrect because it subtracts the product of pressure and volume from internal energy, which is not the correct relationship. Choice C (H = U / PV) is incorrect because it divides internal