Nokea
Certain non-Newtonian fluids exhibit shear thickening behavior. In this case, the fluid's viscosity:
- A. Remains constant with increasing shear rate
- B. Decreases with increasing shear rate (shear thinning)
- C. Increases with increasing shear rate
- D. Depends solely on the applied pressure
Correct Answer: C
Rationale: When a non-Newtonian fluid exhibits shear thickening behavior, its viscosity increases with increasing shear rate. This means that as more force is applied to the fluid, its resistance to flow also increases, resulting in a higher viscosity. This phenomenon is opposite to shear thinning, where viscosity decreases with increasing shear rate. Therefore, in the case of shear thickening behavior, the correct answer is that the fluid's viscosity increases with increasing shear rate. Choices A, B, and D are incorrect because shear thickening behavior specifically involves an increase in viscosity with increasing shear rate, not remaining constant, decreasing, or depending on applied pressure.
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Fluid dynamics is a subfield of fluid mechanics concerned with:
- A. Equilibrium properties of fluids at rest (Fluid Statics)
- B. The motion and behavior of fluids under various conditions
- C. Phase transitions of fluids between liquid, gas, and solid states
- D. Engineering applications of fluids (related but broader than fluid dynamics)
Correct Answer: B
Rationale: Fluid dynamics is the study of fluids in motion and their behavior under different conditions, including how they flow, mix, and interact with their surroundings. It focuses on the dynamic aspects of fluids rather than their static properties when at rest, which is the realm of fluid statics. Phase transitions of fluids between liquid, gas, and solid states are more related to thermodynamics than fluid dynamics. While engineering applications involve fluid dynamics, the field itself is more specialized in studying the movement and behavior of fluids.
When a dielectric material is inserted between the plates of a charged capacitor, what will happen to the capacitance?
- A. Increase
- B. Decrease
- C. Remain the same
- D. Become unpredictable
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 presence of a dielectric material reduces the electric field between the plates, allowing more charge to be stored for a given voltage, thus increasing the capacitance. Choice B is incorrect because adding a dielectric material increases capacitance. Choice C is incorrect because capacitance changes when a dielectric is added. Choice D is incorrect because the effect of a dielectric on capacitance is predictable.
In a scenario where a transverse wave transports energy from north to south, in what direction do the particles in the medium move?
- A. Only north to south
- B. Both northward and southward
- C. Only east to west
- D. Both eastward and westward
Correct Answer: B
Rationale: In a transverse wave, particles of the medium move perpendicular to the direction of energy transport. When the wave transports energy from north to south, the particles in the medium oscillate up and down, causing them to move both northward and southward. Choice A is incorrect because the particles move in both directions, not only from north to south. Choices C and D are incorrect as they mention directions that are not relevant to the scenario described in the question.
Which conclusion can be drawn from Ohm's law?
- A. Voltage and current are inversely proportional when resistance is constant.
- B. The ratio of the potential difference between the ends of a conductor to current is a constant, R.
- C. Voltage is the amount of charge that passes through a point per second.
- D. Power (P) can be calculated by multiplying current (I) by voltage (V).
Correct Answer: B
Rationale: Ohm's law states that the ratio of the potential difference (voltage) between the ends of a conductor to the current flowing through it is a constant. Mathematically, this is represented as V = I x R, where V is voltage, I is current, and R is the constant resistance. Therefore, the correct conclusion that can be drawn from Ohm's law is that the ratio of the potential difference between the ends of a conductor to current is a constant, denoted as R. This relationship is fundamental to understanding the behavior of electrical circuits and the effect of resistance on voltage and current. Choice A is incorrect because Ohm's law actually states that voltage and current are directly proportional when resistance is constant. Choice C is incorrect because voltage is not the amount of charge that passes through a point per second; rather, it is the electric potential energy per unit charge. Choice D is incorrect because although power (P) can be calculated by multiplying current (I) by voltage (V), this is not a conclusion directly drawn from Ohm's law.
Jack stands in front of a plane mirror. If he is 5 feet away from the mirror, how far away from Jack is his image?
- A. 2.5 feet
- B. 3 feet
- C. 4.5 feet
- D. 5 feet
Correct Answer: D
Rationale: When Jack stands in front of a plane mirror, his image appears the same distance behind the mirror as Jack is in front of it. Therefore, if Jack is 5 feet away from the mirror, his image will also appear 5 feet behind the mirror. The total distance from Jack to his image is the sum of these distances, which equals 10 feet. Choices A, B, and C are incorrect because the image distance is not half of the total distance but the same as the object's distance from the mirror.