when a junked car is compacted which statement is true

HESI A2

HESI Exams Quizlet Physics

1. When a junked car is compacted, which statement is true?

A. Its mass increases.
B. Its mass decreases.
C. Its density increases.
D. Its density decreases.

Correct answer: C

Rationale: When a junked car is compacted, its volume decreases while its mass remains the same. As a result, the car's density increases because density is mass divided by volume. Choice A is incorrect because the mass of the car remains the same. Choice B is incorrect because the mass does not decrease. Choice D is incorrect because the density increases as the volume decreases, not decreases.

2. An airplane travels 500 miles northeast and then, on the return trip, travels 500 miles southwest. Which of the following is true?

A. The displacement of the plane is 1,000 miles, and the distance traveled is 0 miles.
B. The displacement of the plane is 1,000 miles, and the distance traveled is 1,000 miles.
C. The displacement of the plane is 0 miles, and the distance traveled is 0 miles.
D. The displacement of the plane is 0 miles, and the distance traveled is 1,000 miles.

Correct answer: D

Rationale: The displacement of an object is the change in position from the starting point to the ending point, regardless of the path taken. In this case, the airplane returns to its original position after traveling 500 miles northeast and then 500 miles southwest. Therefore, the displacement is 0 miles. However, the distance traveled is the total path covered, which is 500 miles northeast plus 500 miles southwest, for a total of 1,000 miles. Choice A is incorrect because the displacement is not the sum of the distances traveled. Choice B is incorrect as it incorrectly states that both the displacement and the distance traveled are 1,000 miles. Choice C is incorrect as it states that both the displacement and the distance traveled are 0 miles, which is not the case.

3. The first law of thermodynamics is a principle of energy conservation. It states that:

A. Energy can be created or destroyed.
B. The total entropy of an isolated system always decreases.
C. Energy can neither be created nor destroyed, only transferred or transformed.
D. The temperature of a system is directly proportional to its entropy.

Correct answer: C

Rationale: The first law of thermodynamics states that energy cannot be created or destroyed; it can only be transferred or converted from one form to another, ensuring energy conservation in any system. Choice A is incorrect because it goes against the principle of energy conservation. Choice B is incorrect as it refers to the second law of thermodynamics, which states that the total entropy of an isolated system always increases. Choice D is incorrect because the temperature of a system is not directly proportional to its entropy.

4. In an electrically neutral atom, the number of:

A. Electrons is equal to protons
B. Protons is equal to neutrons
C. Neutrons are always greater than protons
D. Electrons are always less than protons

Correct answer: A

Rationale: In an electrically neutral atom, the number of electrons is equal to the number of protons. Electrons carry a negative charge, protons carry a positive charge, and neutrons are neutral. Since the atom is electrically neutral, the positive charge of the protons must balance the negative charge of the electrons, making the numbers of electrons and protons equal. Choice B is incorrect because protons are not equal to neutrons in an atom. Choice C is incorrect because neutrons are not always greater than protons, and choice D is incorrect because electrons are not always less than protons in an atom.

5. What is the electric field inside a hollow conductor with a net charge?

A. Remains constant
B. Decreases
C. Zero
D. Becomes unpredictable

Correct answer: C

Rationale: The correct answer is C: Zero. According to Gauss’s Law, the electric field inside a hollow conductor (a conductor with no charge inside but a net charge on its surface) is zero. The charges reside on the outer surface of the conductor, causing the electric field inside to cancel out. Choices A, B, and D are incorrect because the electric field inside a hollow conductor with a net charge is not constant, does not decrease, and does not become unpredictable; it is zero due to the distribution of charges on its surface.