HESI Exams Quizlet Physics

Correct Answer: B

Rationale: The correct answer is B: Permeability is preferred. High permeability in the core of an electromagnet enhances its magnetic field strength by allowing more magnetic flux to pass through, increasing the efficiency of the electromagnet. Resistivity (choice A) would hinder current flow, reducing magnetic field strength. Permittivity (choice C) is related to electric fields, not magnetic fields. Dielectric strength (choice D) is the ability of a material to withstand electric fields, not directly related to enhancing magnetic properties.

Correct Answer: B

Rationale: In an isobaric process (constant pressure), work done is given by W = PΔV. Since the pressure is constant, work done is directly proportional to the volume change. As volume increases, work is done by the system, making it positive. If volume decreases, work is done on the system, making it negative. Choice A is incorrect as work is done even if volume change is zero. Choice C is incorrect as work's sign depends on the direction of volume change. Choice D is incorrect as work done is indeed dependent on pressure and volume change in an isobaric process.

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

Correct Answer: C

Rationale: Step-by-step rationale: 1. Archimedes' principle states that the buoyant force on an object is equal to the weight of the fluid displaced. 2. Submarines adjust their buoyancy by changing the amount of water they displace, allowing them to submerge or resurface. 3. This control of buoyancy is crucial for submarines to navigate underwater efficiently while conserving energy. 4. Choice A is incorrect as density differences affect buoyancy, not causing objects to sink regardless. 5. Choice B is incorrect as airplane lift is generated by the Bernoulli principle and wing design, not Archimedes' principle. 6. Choice D is incorrect as helium balloons float due to buoyancy force exceeding their weight, not overcoming gravity.

Correct Answer: B

Rationale: Step 1: Work is defined as the product of force and displacement in the direction of the force. Step 2: In this scenario, the object is stationary, meaning there is no displacement. Step 3: Without displacement, work done is zero. Step 4: Therefore, the correct answer is B: Not performed. Summary: A: Incorrect because work requires displacement. C: Incorrect as partial work implies partial displacement, which is not the case here. D: Incorrect as it is conclusive that work is not performed due to the absence of displacement.