HESI A2 Physics Quizlet

Correct Answer: B

Rationale: To calculate momentum, we use the formula p = mv, where p is momentum, m is mass, and v is velocity. Given mass = 45g = 0.045kg and velocity = 42m/s. Substituting the values, we get p = 0.045kg * 42m/s = 1.89 kg⋅m/s. Therefore, the correct answer is B (1.89 kg⋅m/s). Choice A: Incorrect. 0.189 kg⋅m/s is obtained by incorrectly calculating the product of mass and velocity. Choice C: Incorrect. 1.07 kg⋅m/s is not the correct calculation of momentum based on the given values. Choice D: Incorrect. 0.93 kg⋅m/s is an incorrect calculation and does not represent the momentum of the baseball accurately.

Correct Answer: B

Rationale: The strength of a magnetic field is measured in units of Tesla (B), named after Nikola Tesla. Tesla is the unit of magnetic flux density. Amperes (A) measure electric current, Volts (C) measure electric potential, and Coulombs (D) measure electric charge. Magnetic fields are not measured in current, potential, or charge units, making B the correct choice.

Correct Answer: B

Rationale: The correct answer is B: ṁ = ρvA. This equation is derived from the continuity equation, which states that mass flow rate ṁ remains constant in steady flow. Mass flow rate ṁ is the product of fluid density ρ, cross-sectional area A, and average velocity v. This relationship is crucial for understanding the behavior of fluids in pipes. Choice A is incorrect because the mass flow rate can be determined using the given equation without any additional information. Choice C is incorrect because Bernoulli's principle is not directly related to the calculation of mass flow rate. Choice D is incorrect because the equation of state for the specific fluid is not required to determine the mass flow rate using the continuity equation.

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: C

Rationale: To calculate current, we use the formula I = P/V, where P is power in watts and V is voltage in volts. In this case, the power is 780 watts and the voltage is 120 volts. Therefore, I = 780/120 = 6.5 amperes. Choice C is correct. Choice A (660 amperes) is incorrect as it is an unrealistic and excessively high value for current in this scenario. Choice B (150 amperes) is incorrect as it does not align with the calculated value using the formula. Choice D (0.15 amperes) is incorrect as it is the decimal form of the correct answer but not expressed in amperes.