HESI A2 Physics Quizlet

Correct Answer: D

Rationale: To compress the spring from 40 cm to 30 cm, we calculate the change in length = 40 cm - 30 cm = 10 cm = 0.1 m. The force needed is given by Hooke's Law: F = k * x, where F is the force, k is the spring constant (20 N/m), and x is the change in length (0.1 m). Therefore, F = 20 N/m * 0.1 m = 2 N. Choice D (2 N) is correct because it correctly applies Hooke's Law. Choices A, B, and C are incorrect because they do not correctly calculate the force based on the given spring constant and change in length.

Correct Answer: D

Rationale: The correct answer is D. Displacement is the shortest distance between the initial and final points of the walk. Since Jon walks around a rectangular park, his start and end points are the same, hence the displacement is 0 km. The distance traveled is the actual path length covered, which is equal to the perimeter of the rectangle (2+2+1+1=6 km). Therefore, the correct statement is that the displacement of his walk is 0 kilometers, and the distance traveled is 6 kilometers. Summary: A: Incorrect. Displacement cannot be greater than the distance traveled when walking in a closed loop. B: Incorrect. Displacement should be 0 km for a closed loop walk. C: Incorrect. Displacement cannot be greater than the total perimeter of the walk.

Correct Answer: C

Rationale: To calculate work, we use the formula Work = Force × Distance. In this scenario, Amanda exerts a force of 100 N to push the lawnmower a total distance of 20 rows × 30 meters/row = 600 meters. Therefore, the work done is 100 N × 600 m = 60,000 N⋅m. This is why choice C, 60,000 N⋅m, is correct. Choices A and B are incorrect as they do not accurately calculate the work done. Choice D is also incorrect as we can determine the work done using the provided information.

Correct Answer: A

Rationale: The correct answer is A: Its energy is halved. Kinetic energy is calculated using the formula KE = 0.5 * mass * velocity^2. Since kinetic energy is directly proportional to the square of velocity, if the speed drops from 60 mph to 30 mph, the kinetic energy will be reduced by a factor of 4 (30^2/60^2), which means it is halved. Summary: B: Its energy is doubled - Incorrect. Decreasing the speed from 60 mph to 30 mph reduces the kinetic energy, not double it. C: Its energy is quadrupled - Incorrect. Decreasing the speed results in a decrease in kinetic energy, not quadrupling it. D: Its energy is divided by four - Incorrect. The kinetic energy is reduced by a factor of 4, not divided by four.

Correct Answer: B

Rationale: The correct answer is B: The speed of light. In Einstein's mass-energy equation (E=mc^2), 'c' represents the speed of light in a vacuum, which is approximately 3 x 10^8 meters per second. This constant is crucial in the equation as it shows the relationship between mass and energy. The speed of light is a fundamental physical constant and plays a significant role in various aspects of physics, including relativity. Incorrect choices: A: Distance in centimeters - Distance in centimeters is not represented by 'c' in Einstein's equation. C: Degrees Celsius - 'c' does not represent temperature in degrees Celsius in the equation. D: Centrifugal force - 'c' does not represent centrifugal force in the equation.