HESI A2
HESI A2 Physics Questions
Question 1 of 5
Which vehicle has the greatest momentum?
Correct Answer: D
Rationale: The momentum of an object is calculated by multiplying its mass by its velocity. The momentum formula is p = m v, where p is momentum, m is mass, and v is velocity. Comparing the momentum of each vehicle: A: 9,000 kg 3 m/s = 27,000 kg·m/s B: 2,000 kg 24 m/s = 48,000 kg·m/s C: 1,500 kg 29 m/s = 43,500 kg·m/s D: 500 kg 89 m/s = 44,500 kg·m/s. Therefore, the glider (500-kg) traveling at 89 m/s has the greatest momentum of 44,500 kg·m/s, making it the correct choice. Options A, B, and C have lower momentum values compared to option D, proving that the 500-kg glider traveling at 89 m/s has the highest momentum among the given vehicles.
Question 2 of 5
If a force of 12 kg stretches a spring by 3 cm, how far will the spring stretch when a force of 30 kg is applied?
Correct Answer: B
Rationale: The extension of a spring is directly proportional to the force applied. In this case, the force increases from 12 kg to 30 kg, which is a 2.5 times increase. Therefore, the extension of the spring will also increase by 2.5 times. Given that the spring stretches 3 cm with a force of 12 kg, multiplying 3 cm by 2.5 gives us the extension of the spring when a force of 30 kg is applied, which equals 7.5 cm. Therefore, the correct answer is 7.5 cm. Choice A, 6 cm, is incorrect because it does not account for the proportional increase in force. Choice C, 9 cm, and Choice D, 10.5 cm, are incorrect as they overestimate the extension of the spring by not considering the direct proportionality between force and extension.
Question 3 of 5
A circular running track has a circumference of 2,500 meters. What is the radius of the track?
Correct Answer: B
Rationale: The radius of a circular track can be calculated using the formula: Circumference = 2 π radius. Given that the circumference of the track is 2,500 m, we can plug this into the formula and solve for the radius: 2,500 = 2 π radius. Dividing both sides by 2π gives: radius = 2,500 / (2 3.1416) ≈ 397.89 m. Therefore, the closest answer is 400 m, making option B the correct choice. Option A (1,000 m) is too large, option C (25 m) is too small, and option D (12 m) is significantly smaller than the calculated radius.
Question 4 of 5
Two 5-ohm resistors are placed in series and wired into a 100-V power supply. What current flows through this circuit?
Correct Answer: B
Rationale: In a series circuit, the total resistance is the sum of the individual resistances. Therefore, the total resistance in this circuit is 5 ohms + 5 ohms = 10 ohms. Using Ohm's Law (V = I R), we can find the current (I) by dividing the voltage (V) by the total resistance (R). I = V / R = 100 V / 10 ohms = 10 A. Choice A (2 A) is incorrect because it does not account for the total resistance of the circuit. Choice C (20 A) and Choice D (50 A) are also incorrect as they provide values that are not consistent with the calculations based on the given values in the question.
Question 5 of 5
An object with a charge of 4 μC is placed 1 meter from another object with a charge of 2 μC. What is the magnitude of the resulting force between the objects?
Correct Answer: A
Rationale: To find the magnitude of the resulting force between two charges, we can use Coulomb's law, which states that the force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. The formula for Coulomb's law is: F = k (|q1 q2| / r²), where F is the force, k is the Coulomb constant, q1 and q2 are the charges, and r is the distance between the charges. Substituting the given values into the formula: F = (9 10â¹ N·m²/C²) ((4 10â»â¶ C) (2 10â»â¶ C) / (1 m)²) = 0.04 N. Therefore, the magnitude of the resulting force between the objects is 0.04 N.