HESI A2 Physics

Correct Answer: B

Rationale: The correct answer is B: The bicycle has less kinetic energy than the car. Kinetic energy is calculated as KE = 0.5 * mass * velocity^2. Since both vehicles are traveling at the same speed, the one with greater mass (the car) will have more kinetic energy. The bicycle, being lighter than the car, will have less kinetic energy despite moving at the same speed. Other choices are incorrect because A is false as explained, C is incorrect as the vehicles have different masses, and D is incorrect as both vehicles are in motion, so both have kinetic energy.

Correct Answer: C

Rationale: The correct answer is C because when the box falls, it converts its potential energy (due to its height above the floor) into kinetic energy (due to its motion). As it falls, its potential energy decreases while its kinetic energy increases. Therefore, the box has both kinetic and potential energy after it falls. A is incorrect because the box still has kinetic energy after hitting the floor. B is incorrect because the box gains kinetic energy as it falls. D is incorrect because the box retains some kinetic energy even after hitting the floor.

Correct Answer: A

Rationale: The correct answer is A: Experience a net buoyant force acting upwards. When the specific gravity of an object is greater than 1, it means the object is denser than the reference fluid. According to Archimedes' Principle, a submerged object experiences an upward buoyant force equal to the weight of the fluid it displaces. Since the object is denser than the fluid, it will displace less fluid, resulting in a net buoyant force acting upwards. Choice B is incorrect because a denser object will displace less fluid, leading to an upward buoyant force. Choice C is incorrect because neutrally buoyant objects have an SG equal to that of the reference fluid. Choice D is incorrect because the object's volume is not needed to determine the direction of the buoyant force based on specific gravity alone.

Correct Answer: D

Rationale: To calculate work, we use the formula W = F*d, where W is work, F is force, and d is distance. In this case, the force is 15 N and the distance is 3 m. So, W = 15 N * 3 m = 45 N⋅m. Therefore, the correct answer is D. Choice A is incorrect as it incorrectly calculates work by dividing force by distance. Choice B is incorrect as it only provides the correct unit for work, not the actual calculation. Choice C is incorrect as it incorrectly multiplies force and distance to get the wrong result.

Correct Answer: C

Rationale: The correct answer is C because psychrometrics specifically deals with the properties of mixtures of moist air and water vapor. It focuses on the study of air-water vapor mixtures and their interactions, such as humidity, temperature, and moisture content. Choice A (Ideal gases) is incorrect because psychrometrics goes beyond the behavior of ideal gases. Choice B (Magnetic materials) is incorrect as it is unrelated to the study of air-water vapor mixtures. Choice D (Nuclear reactions) is also incorrect as it pertains to nuclear physics, not the properties of air-water vapor mixtures. In summary, the correct answer C aligns with the specific focus of psychrometrics on moist air and water vapor properties, making it the most appropriate choice.