why does potential energy increase as particles approach each other

HESI A2

HESI Exams Quizlet Physics

1. Why does potential energy increase as particles approach each other?

A. Attractive forces increase.
B. Attractive forces decrease.
C. Repulsive forces increase.
D. Repulsive forces decrease.

Correct answer: C

Rationale: The correct answer is C: Repulsive forces increase. As particles approach each other, the distance between them decreases, causing the repulsive forces between the particles to increase. This increase in repulsive forces leads to an increase in potential energy as the particles resist being pushed closer together. Choices A and B are incorrect because attractive forces do not increase or decrease in this scenario. Choice D is incorrect because repulsive forces actually increase as particles get closer, leading to a rise in potential energy.

2. How do a scalar quantity and a vector quantity differ?

A. A scalar quantity has both magnitude and direction, and a vector does not.
B. A scalar quantity has direction only, and a vector has only magnitude.
C. A vector has both magnitude and direction, and a scalar quantity has only magnitude.
D. A vector has only direction, and a scalar quantity has only magnitude.

Correct answer: C

Rationale: The correct answer is C. The main difference between a scalar quantity and a vector quantity lies in the presence of direction. A vector quantity has both magnitude and direction, while a scalar quantity has magnitude only, without any specified direction. Examples of scalar quantities include distance, speed, temperature, and energy, whereas examples of vector quantities include displacement, velocity, force, and acceleration. Choices A, B, and D are incorrect because they incorrectly describe the characteristics of scalar and vector quantities.

3. When a gas is compressed isothermally, we can say that:

A. The gas performs work on the surroundings, and its internal energy increases.
B. The gas performs work on the surroundings, and its internal energy decreases.
C. The surroundings perform work on the gas, and its internal energy increases.
D. The surroundings perform work on the gas, and its internal energy decreases.

Correct answer: D

Rationale: When a gas is compressed isothermally, the surroundings perform work on the gas. In this process, since the temperature remains constant (isothermal), the internal energy of the gas does not change. Therefore, the correct answer is that the surroundings perform work on the gas, and its internal energy decreases. Choices A, B, and C are incorrect because they incorrectly describe the direction of work and the change in internal energy during an isothermal compression.

4. As a vehicle positioned at the peak of a hill rolls downhill, its potential energy transforms into:

A. Thermal energy
B. Neither thermal nor kinetic energy
C. A combination of thermal and kinetic energy
D. Kinetic energy

Correct answer: D

Rationale: The correct answer is D: Kinetic energy. Potential energy is converted into kinetic energy as the vehicle moves downhill. Kinetic energy is the energy possessed by a moving object. Thermal energy is not produced in this scenario because the energy transformation is mainly from potential to kinetic energy, not involving heat generation. Choices A, B, and C are incorrect because the primary energy transformation in this scenario is from potential to kinetic energy, not involving thermal energy.

5. Which of the following describes a vector quantity?

A. 5 miles per hour due southwest
B. 5 miles per hour
C. 5 miles
D. None of the above

Correct answer: A

Rationale: A vector quantity is characterized by both magnitude and direction. In the provided options, choice A, '5 miles per hour due southwest,' fits this definition as it includes both the magnitude (5 miles per hour) and the direction (southwest), making it a vector quantity. Choices B and C only provide the magnitude without indicating any direction, hence they do not represent vector quantities.