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: 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.

Correct Answer: C

Rationale: The correct answer is C: Hydrogen gas. This is because gases are highly affected by changes in temperature due to their particles having more kinetic energy. When temperature increases, gas particles move faster, increasing pressure. Conversely, when temperature decreases, gas particles move slower, decreasing pressure. In contrast, liquid nitrogen (choice A) and salt crystals (choice B) are not as affected by temperature changes due to their stable structures. Iron filings (choice D) are also not significantly affected by temperature changes as they are solid and have a fixed shape and volume.

Correct Answer: B

Rationale: To find the frequency, we use the formula: speed = wavelength x frequency. Given speed = 12 m/s and wavelength = 2 m, we can rearrange the formula to solve for frequency: frequency = speed / wavelength = 12 m/s / 2 m = 6 Hz. Choice A (38.4 Hz) is incorrect as it would be the frequency if the wavelength was 0.3125 m, not 2 m. Choice C (4.6 Hz) and D (3.75 Hz) are also incorrect as they do not match the calculated frequency of 6 Hz based on the given values.

Correct Answer: B

Rationale: The correct answer is B: Newton's second law of motion. This law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. The formula for this relationship is F = ma, where F is the force applied, m is the mass of the object, and a is the acceleration produced. This equation clearly expresses the relationship between acceleration and force. Now, let's analyze why the other choices are incorrect: A: Newton's first law of motion, also known as the law of inertia, states that an object at rest will remain at rest, and an object in motion will remain in motion unless acted upon by an external force. This law does not directly relate to the relationship between acceleration and force. C: Newton's third law of motion states that for every action, there is an equal and opposite reaction. This law describes the interaction between two objects and their forces, not the relationship between acceleration and force. D: Saying