HESI A2
HESI A2 Physics Quizlet Questions
Question 1 of 5
The Reynolds number (Re) is a dimensionless quantity used to characterize:
Correct Answer: B
Rationale: The Reynolds number is a dimensionless quantity used to characterize the flow regime, specifically whether it is laminar (smooth) or turbulent (chaotic). It depends on the velocity of the fluid, its characteristic length (such as pipe diameter), and its viscosity. A low Reynolds number indicates laminar flow, while a high Reynolds number suggests turbulence.
Choices A, C, and D are incorrect because the Reynolds number is not related to fluid density, surface tension effects, or buoyancy force magnitude.
Question 2 of 5
Amanda uses 100 N of force to push a lawnmower around her lawn. If she mows 20 rows measuring 30 meters each, how much work does she do?
Correct Answer: C
Rationale: The work done by Amanda pushing the lawnmower is calculated by multiplying the force applied (100 N) by the distance over which the force is applied (the total distance mowed). Since Amanda mows 20 rows, each measuring 30 meters, the total distance mowed is 20 rows x 30 meters/row = 600 meters.
Therefore, the work done is 100 N x 600 m = 60,000 Nâ‹…m. Option A and B are incorrect as they do not account for the total distance mowed. Option D is incorrect as the work done can be accurately calculated based on the information provided.
Question 3 of 5
Power (P) represents the rate of work done. Which formula accurately depicts power?
Correct Answer: D
Rationale: Power (P) is defined as the rate of work done over time. The correct formula for power is P = W/t, where W is the work done, and t is the time taken.
Therefore, option D, P = F / t, correctly represents power as work divided by time. Option A, P = W / F, is incorrect as it represents work divided by force, not power. Option B, P = d / t, is incorrect as it represents distance divided by time, not power. Option C, P = W x t, is incorrect as it represents work multiplied by time, not power. It's important to understand the distinction between work, power, force, time, and other related concepts to solve physics problems accurately.
Question 4 of 5
A spring has a spring constant of 20 N/m. How much force is needed to compress the spring from 40 cm to 30 cm?
Correct Answer: D
Rationale: The change in length of the spring is 40 cm - 30 cm = 10 cm = 0.10 m. The force required to compress or stretch a spring is given by Hooke's Law: F = k x, where F is the force, k is the spring constant (20 N/m in this case), and x is the change in length (0.10 m). Substituting the values into the formula: F = 20 N/m 0.10 m = 2 N.
Therefore, the correct answer is 2 N.
Choice A (200 N) is incorrect because it miscalculates the force.
Choice B (80 N) is incorrect as it does not apply Hooke's Law correctly.
Choice C (5 N) is incorrect as it underestimates the force required.
Question 5 of 5
Which object below has the same density?
Correct Answer: A
Rationale: Density is calculated by dividing the mass of an object by its volume. The density of object A is 6.5 g / 16.25 cm3 = 0.4 g/cm3. The density of object B is 80 g / 32 cm3 = 2.5 g/cm3. The density of object C is 48 g / 22 cm3 = 2.18 g/cm3. The density of object D is 100 g / 250 cm3 = 0.4 g/cm3. Objects A and D have the same density of 0.4 g/cm3.
Therefore, the correct answer is A as it has the same density as object D, making them the only objects with a density of 0.4 g/cm3.