HESI Exams Quizlet Physics

Correct Answer: D

Rationale: The correct answer is D: To allow the circuit to open and close. A switch in a circuit functions by either completing or interrupting the flow of current. When the switch is closed, it provides a path for the current to flow, allowing the circuit to be operational. Conversely, when the switch is opened, it breaks the circuit, halting the flow of current. This on-off capability of a switch enables control over the circuit, making it a fundamental component in regulating the flow of electricity. Choices A, B, and C are incorrect because a switch does not reverse the direction of current, increase voltage, or alter the resistance of wires in a circuit.

Correct Answer: C

Rationale: The correct answer is C because a vector quantity has both magnitude and direction, such as velocity, while a scalar quantity only has magnitude, like speed. A scalar quantity can be represented by a single numerical value, whereas a vector requires both a numerical value and a specific direction to fully describe it. Choices A, B, and D are incorrect because they misrepresent the defining characteristics of scalar and vector quantities. Choice A is incorrect because a vector quantity does have direction. Choice B is incorrect because it states that a scalar quantity has direction, which is inaccurate. Choice D is incorrect because it states that a scalar quantity has direction, which is also inaccurate.

Correct Answer: B

Rationale: The correct answer is B because as a raindrop falls, air resistance increases, counteracting the force of gravity. Initially, gravity pulls the raindrop down, causing it to accelerate. However, as the raindrop gains speed, air resistance becomes stronger, eventually balancing out the gravitational force. This results in a constant velocity rather than acceleration. A: Gravity does pull the raindrop down, but it doesn't do so at a constant rate. The acceleration due to gravity is constant but is countered by air resistance. C: The mass of the raindrop remains constant as it falls, so its mass decreasing is not a factor in its speed. D: Objects in motion do not necessarily decelerate over distance; in the case of the raindrop, air resistance prevents further acceleration.

Correct Answer: D

Rationale: The correct answer is D. Capillarity is due to the cohesive forces between liquid molecules, leading to surface tension at the liquid-gas interface. This results in the liquid rising or falling in narrow tubes due to intermolecular forces overcoming gravity. A: Buoyancy and pressure differentials do not directly explain capillarity, which is driven by surface tension. B: Density variations and compressibility do not play a significant role in capillarity compared to surface tension. C: Viscous dissipation and inertial effects are not the primary factors influencing capillarity; it is mainly driven by intermolecular forces.

Correct Answer: A

Rationale: To calculate momentum, we use the formula p = mv, where p is momentum, m is mass, and v is velocity. Since momentum is conserved, the momentum of the 2,000-kg car is equal to the momentum of the 1,500-kg car. Setting the two momentum equations equal to each other, we get 2000*15 = 1500*v, where v is the velocity of the 1,500-kg car to generate the same momentum. Solving for v, we get v = (2000*15) / 1500 = 20 m/s. Therefore, to generate the same momentum as the 2,000-kg car, the 1,500-kg car would need to accelerate to 20 m/s. Choice A is correct. Choices B, C, and D are incorrect as changing the mass or a combination of adding mass and velocity will not lead to the 1,500-kg car generating