HESI Exams Quizlet Physics

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: 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: The correct answer is B: Water. Density is mass per unit volume. Water has the highest density among the options due to its relatively high mass compared to its volume. Mist (A) is a dispersion of water droplets in the air, which has lower density. Steam (C) is water vapor with lower density than liquid water. Ice (D) has lower density than liquid water because its molecules are more spread out in a solid state. Water's density is highest due to its compact molecular arrangement in its liquid form.

Correct Answer: B

Rationale: The correct answer is B: 1.8 N. The repulsive force between two charges can be calculated using Coulomb's Law: F = k * (q1 * q2) / r^2, where k is the electrostatic constant (9 x 10^9 N m^2/C^2), q1 and q2 are the charges (5 μC each), and r is the distance between the charges (25 cm = 0.25 m). Plugging in the values, we get F = (9 x 10^9) * (5 x 10^-6) * (5 x 10^-6) / (0.25)^2 = 1.8 N. Choice A is incorrect because it is too low. Choice C is incorrect because it represents a very low force. Choice D is incorrect because it is equivalent to 5 x 10^-3 = 0.005 N, which is not the correct value

Correct Answer: C

Rationale: The correct answer is C because when the car hits the ground, all of its potential energy is converted into kinetic energy. As the car falls, potential energy decreases while kinetic energy increases. Therefore, the car does not retain any potential energy when it hits the ground. Choice A is correct as the potential energy at the height can be calculated as mgh (mass x gravity x height). Choice B is correct as potential energy is converted to kinetic energy as the car falls. Choice D is incorrect as the potential energy is first converted to kinetic energy, not directly to sound energy.