HESI A2 Physics Practice Test

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: C

Rationale: To calculate kinetic energy, we use the formula KE = 0.5 * mass * velocity^2. Plugging in the values (0.5 * 500 kg * (10 m/s)^2), we get 0.5 * 500 * 100 = 25000 J. Therefore, the correct answer is C (2.5 * 10^4 J). Choice A (50 J) is incorrect as it is too low. Choice B (250 J) is incorrect, as it only considers the mass without accounting for the velocity. Choice D (5.0 * 10^5 J) is incorrect as it overestimates the kinetic energy due to incorrect calculations.

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: C

Rationale: The gravitational force between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them (F = G * (m1 * m2) / r^2). When the distance is halved, the force quadruples (2^2 = 4 times). Therefore, if the original force is 12 units, when the distance is halved, the new force will be 12 * 4 = 48 units. Therefore, the correct answer is C. Choice A (3 units) is incorrect because the force increases when the distance is halved. Choice B (6 units) is incorrect as well, as the force should increase more when the distance is halved. Choice D (48 units) is incorrect because the new force of attraction is not doubled but quadrupled when the distance is halved.

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