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: To determine the stretch of the spring when a 30 kg force is applied, we first calculate the spring constant using Hooke's Law: F = kx. Given F1 = 12 kg and x1 = 3 cm, k = F1/x1 = 12 kg / 0.03 m = 400 N/m. Then, for F2 = 30 kg, x2 = F2 / k = 30 kg / 400 N/m = 0.075 m = 7.5 cm. Therefore, choice B (7.5 cm) is the correct answer. Choices A, C, and D are incorrect as they do not align with the calculated value using Hooke's Law.

Correct Answer: B

Rationale: To find the radius of the circular track, we use the formula: circumference = 2 * π * radius. Given circumference = 2,500m, we can rearrange the formula to solve for radius: radius = circumference / (2 * π) = 2,500 / (2 * 3.14) ≈ 398.73m. Therefore, the closest option to the calculated radius is B: 400m. Incorrect answers: A: 1,000m - This is twice the correct radius, not accurate. C: 25m - This is 10 times smaller than the correct radius, not accurate. D: 12m - This is much smaller than the correct radius, not accurate.

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.

Correct Answer: A

Rationale: To determine the velocity of a wave, you need to use the formula v = fλ, where v is the velocity, f is the frequency, and λ is the wavelength. By multiplying the frequency by the wavelength (option A), you are essentially applying the correct formula for calculating wave velocity. This is because the velocity of a wave is directly proportional to both its frequency and wavelength. Option B (adding the frequency and wavelength) and Option C (subtracting the wavelength from the frequency) do not align with the correct formula for wave velocity calculation, as it involves multiplication rather than addition or subtraction. Option D (dividing the wavelength by the frequency) is also incorrect because the correct operation for determining wave velocity is multiplication, not division.