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: A

Rationale: The correct answer is A: Pressure. Pumps increase fluid pressure by adding energy to the fluid. When the fluid flows through the pump, it gains kinetic energy which is then converted into pressure energy. Choice B is incorrect because pumps do not primarily aim to increase velocity only. Choice C is incorrect as while pumps do increase both pressure and velocity, the primary goal is to increase pressure. Choice D is incorrect as pumps are specifically designed to increase either pressure, velocity, or both, depending on the application.

Correct Answer: D

Rationale: The correct answer is D: Cannot be created or destroyed. According to the law of conservation of energy, energy can neither be created nor destroyed, but only transformed from one form to another. This principle is a fundamental law of physics known as the first law of thermodynamics. Any process involving energy transfer must adhere to this law. Choices A, B, and C are incorrect because they contradict this fundamental principle. Energy cannot be created out of nothing or disappear completely; it can only change forms.

Correct Answer: D

Rationale: To calculate impulse, we use the formula Impulse = Change in Momentum. First, calculate the initial momentum: initial momentum = 10 kg * 5 m/s = 50 kg⋅m/s. Then, calculate the final momentum: final momentum = 10 kg * 15 m/s = 150 kg⋅m/s. The change in momentum is final momentum - initial momentum = 150 kg⋅m/s - 50 kg⋅m/s = 100 kg⋅m/s. Therefore, the impulse applied to the object is 100 kg⋅m/s. Choice D is correct as it correctly represents the impulse value. Choices A, B, and C are incorrect as they do not accurately reflect the calculated impulse value.

Correct Answer: B

Rationale: The correct answer is B: Conduction. When the hot cup of coffee is placed on a cold table, heat transfer primarily occurs through conduction. This is because heat is transferred from the hot coffee to the cold table through direct contact. Conduction is the process of heat transfer through a material due to direct molecular collisions. Radiation (choice A) involves the transfer of heat through electromagnetic waves, which is not the primary process in this scenario. Convection within the coffee (choice C) involves the transfer of heat through the movement of fluid particles, but in this case, the primary heat transfer mechanism is conduction. Choice D is incorrect as it suggests a combination of conduction and convection, when conduction is the dominant process in this situation.