HESI Exams Quizlet Physics

Correct Answer: A

Rationale: The momentum of an object is calculated by multiplying its mass by its velocity. In this case, for option A, the momentum of the car is calculated as 1,250 kg x 5 m/s = 6,250 kg*m/s. This is greater than the momentum of the other choices. For option B, the momentum of the person is 80 kg x 4 m/s = 320 kg*m/s, which is less than the car's momentum. For option C, the momentum of the meteorite is 10 kg x 600 m/s = 6,000 kg*m/s, which is also less than the car's momentum. For option D, the momentum of the rock is 0.5 kg x 40 m/s = 20 kg*m/s, making it the smallest momentum among the choices. Therefore, the car moving at 5 m/s has the greatest momentum due to its higher mass and velocity compared to the other objects.

Correct Answer: A

Rationale: The correct answer is A: 10 m/s. Velocity is calculated by dividing the distance traveled by the time taken. In this case, velocity = 100m / 10s = 10 m/s. Choice B, 90 m/s, is incorrect because it is not the accurate calculation. Choice C, 110 m/s, and choice D, 1,000 m/s, are both incorrect as they do not align with the correct formula for calculating velocity. The key is to remember that velocity is a vector quantity that includes both speed and direction, and in this case, we are only concerned with the speed of the object, making choice A the correct answer.

Correct Answer: C

Rationale: The correct answer is C: Gay-Lussac's law. This law states that the pressure of a gas is directly proportional to its temperature when volume is constant. When a car is driven for a long time, the tires heat up due to friction with the road, causing the air inside to heat up as well. According to Gay-Lussac's law, as the temperature increases, the pressure of the gas also increases. Choice A, Boyle's law, states that pressure and volume are inversely proportional at constant temperature. Choice B, Charles' law, states that volume and temperature are directly proportional at constant pressure. Choice D, Dalton's law, is about the total pressure of a gas mixture being the sum of the partial pressures of the individual gases. These laws do not directly explain why the pressure in the tires of a car increases with driving.

Correct Answer: C

Rationale: To find the frequency of the wave, we use the formula: speed = wavelength x frequency. Given speed = 20 m/s and wavelength = 4 m, we rearrange the formula to solve for frequency: frequency = speed / wavelength = 20 m/s / 4 m = 5 Hz. Therefore, the correct answer is C: 24 s^-1. Choice A is incorrect as it does not match the calculated frequency. Choices B and D are also incorrect as they do not align with the calculated frequency based on the given information.

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