Nokea
Jon walks all the way around a rectangular park that is 1 km 2 km. Which statement is true about Jon's walk?
- A. The displacement of his walk is 3 kilometers, and the distance traveled is 0 kilometers.
- B. The displacement of his walk is 0 kilometers, and the distance traveled is 16 kilometers.
- C. The displacement of his walk is 6 kilometers, and the distance traveled is 0 kilometers.
- D. The displacement of his walk is 0 kilometers, and the distance traveled is 6 kilometers.
Correct Answer: D
Rationale: Jon walks all the way around a rectangular park that is 1 km 2 km, which means he walks a total distance of 6 kilometers (1 km + 2 km + 1 km + 2 km = 6 km). However, the displacement of his walk is 0 kilometers because he starts and ends at the same point after completing the rectangular path around the park. Displacement refers to the change in position from the starting point to the ending point, regardless of the actual distance traveled. Choice A is incorrect because the total distance traveled by Jon is 6 kilometers, not 0 kilometers. Choice B is incorrect as the displacement is not 0 kilometers, and the distance traveled is 6 kilometers, not 16 kilometers. Choice C is incorrect because the displacement is 0 kilometers, and the distance traveled is 6 kilometers, not 0 kilometers.
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The strength of a magnetic field is measured in units of:
- A. Amperes
- B. Tesla
- C. Volts
- D. Coulombs
Correct Answer: B
Rationale: The Tesla (T) is the unit of measurement for the strength of a magnetic field. One Tesla is defined as one weber per square meter. Amperes (choice A) measure electric current, Volts (choice C) measure electric potential, and Coulombs (choice D) measure electric charge, making them incorrect choices for measuring the strength of a magnetic field.
For steady, incompressible flow through a pipe, the mass flow rate (á¹) is related to the fluid density (Ï), cross-sectional area (A), and average velocity (v) via the continuity equation:
- A. á¹ cannot be determined without additional information
- B. á¹ = ÏvA
- C. Bernoulli's principle is solely applicable here
- D. The equation of state for the specific fluid is required
Correct Answer: B
Rationale: The continuity equation for steady, incompressible flow states that the mass flow rate is the product of the fluid's density, velocity, and cross-sectional area. Hence, á¹ = ÏvA. Choice A is incorrect because the mass flow rate can be determined using the given formula. Choice C is incorrect as Bernoulli's principle does not directly relate to the mass flow rate calculation. Choice D is incorrect as the equation of state is not needed to calculate the mass flow rate in this scenario.
Entropy (S) is a thermodynamic property related to the system's disorder. According to the second law of thermodynamics, in a spontaneous process:
- A. The total entropy of the system and surroundings increases.
- B. The total entropy of the system and surroundings decreases.
- C. The total entropy of the system remains constant.
- D. The total entropy of the surroundings increases, while the system's entropy decreases.
Correct Answer: A
Rationale: The second law of thermodynamics asserts that the entropy of an isolated system (or the combined system and surroundings) will always increase in a spontaneous process, reflecting an increase in disorder. Therefore, the correct answer is that the total entropy of the system and surroundings increases. Choice B is incorrect because entropy always tends to increase in a spontaneous process, as dictated by the second law of thermodynamics. Choice C is incorrect as entropy typically increases in natural processes. Choice D is incorrect because the second law of thermodynamics states that the total entropy of the system and surroundings always increases in a spontaneous process.
In a static fluid, pressure (P) at a depth (h) is governed by the hydrostatic equation:
- A. P = Ïgh
- B. P = γh
- C. P = μgh
- D. P = bh
Correct Answer: A
Rationale: The correct formula for the pressure at a certain depth in a fluid according to the hydrostatic equation is P = Ïgh. Here, Ï represents the fluid's density, g is the gravitational acceleration, and h is the depth. This formula shows that pressure increases linearly with the density of the fluid, the acceleration due to gravity, and the depth. Choices B, C, and D are incorrect because they do not accurately represent the relationship between pressure, density, gravitational acceleration, and depth in a static fluid.
According to the Law of Universal Gravitation, the gravitational force between two objects is directly proportional to what factor?
- A. the gravitational constant
- B. the distance between them
- C. the product of their masses
- D. the square of the distance between them
Correct Answer: C
Rationale: According to the Law of Universal Gravitation, the gravitational force between two objects is directly proportional to the product of their masses. The equation is: F = G (mâ‚ mâ‚‚) / r², where F is the gravitational force, G is the gravitational constant, mâ‚ and mâ‚‚ are the masses of the two objects, and r is the distance between them. Choice A is incorrect because the gravitational constant is a constant value. Choice B is incorrect because the distance between the objects affects the strength of the gravitational force inversely proportional to the square of the distance, not directly proportional. Choice D is incorrect as it represents the inverse square law, where the gravitational force decreases with the square of the distance between the objects.