HESI A2 Physics Practice Test

Correct Answer: A

Rationale: When a dielectric material is inserted between the plates of a charged capacitor, the capacitance will increase. This is because the dielectric reduces the electric field between the plates, which allows for more charge to be stored for a given potential difference. The dielectric polarization enhances the capacitance. The other choices are incorrect because capacitance does not decrease or remain the same when a dielectric is added, and it is not unpredictable as the relationship between capacitance and dielectric constant is well-defined.

Correct Answer: B

Rationale: Faraday's law of electromagnetic induction states that a changing magnetic field in a conductor induces an electromotive force (EMF) according to the Faraday's law equation. This induced EMF creates a current flow in the conductor. The other choices are incorrect because an increase in resistance (choice A) would oppose the current induced by the changing magnetic field, static electric charge (choice C) is not related to induction, and a decrease in capacitance (choice D) is not directly affected by a changing magnetic field.

Correct Answer: A

Rationale: Rationale: An ideal fluid exhibits zero shear stress at any strain rate. This is because an ideal fluid is assumed to have no resistance to flow, resulting in no shear stress being generated regardless of the strain rate. This is a fundamental characteristic of an ideal fluid and distinguishes it from real fluids that exhibit varying levels of shear stress. Summary: - Choice A is correct as an ideal fluid exhibits zero shear stress at any strain rate. - Choice B is incorrect as it describes a Newtonian fluid which has a linear relationship between shear stress and strain rate. - Choice C is incorrect as it describes a Non-Newtonian fluid with a non-linear relationship between shear stress and strain rate. - Choice D is incorrect as it describes the temperature dependence of viscosity, which is not a defining characteristic of an ideal fluid.

Correct Answer: B

Rationale: The correct answer is B: 1.8 m/s. To find the speed of the waves, we use the formula speed = distance/time. The horizontal distance between crests is 9 meters. Since the waves hit the shore every 5 seconds, the time taken is 5 seconds. Therefore, speed = 9m / 5s = 1.8 m/s. Choice A (1.2 m/s) is incorrect because it does not match the calculated speed based on the given information. Choice C (2.0 m/s) and Choice D (2.4 m/s) are also incorrect as they are not the correct calculated speed based on the given data.

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.