HESI A2 Physics Practice Test

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: B

Rationale: The correct answer is B: Boundary layer separation. When a fluid encounters a bluff body, such as a car, the flow separates behind the object due to pressure differences, creating a region of low pressure. This separation of the boundary layer results in increased drag on the object. Cavitation (A) is the formation of vapor bubbles due to low pressure, not specific to bluff bodies. The Bernoulli effect (C) refers to the relationship between fluid speed and pressure, not directly related to flow separation. Drag crisis (D) is a sudden decrease in drag experienced by an object at high speeds, not directly related to flow separation behind a bluff body.

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

Correct Answer: C

Rationale: The correct answer is C because in shear thickening behavior, the fluid's viscosity increases with increasing shear rate. As more force is applied, the fluid's particles align in a way that increases resistance to flow, leading to higher viscosity. Choices A and B are incorrect because shear thickening involves a change in viscosity with shear rate. Choice D is incorrect as viscosity in non-Newtonian fluids is influenced by shear rate, not just applied pressure.

Correct Answer: D

Rationale: To calculate momentum, we use the formula: momentum = mass x velocity. Given mass = 5 kg and velocity = 5 m/s, the momentum is 5 kg x 5 m/s = 25 kg⋅m/s. Therefore, choice D (25 kg⋅m/s) is the correct answer. Choice A (10 kg⋅m/s) is incorrect as it doesn't account for both mass and velocity. Choice B (16.2 km/h) is incorrect as it is a unit conversion for speed, not momentum. Choice C (24.75 kg⋅m/s) is incorrect as it doesn't match the calculated momentum value.