HESI A2 Physics Practice Test

Correct Answer: B

Rationale: The correct expression for work (W) is W = F x d. Work is defined as the product of the force applied (F) in the direction of motion and the displacement (d) of the object. Multiplying force by displacement gives the total energy transferred to the object. Option A (W = F / d) is incorrect because dividing force by distance does not represent work. Option C (W = d / F) is incorrect as work is not calculated by dividing distance by force. Option D (W = F^2 x d) is incorrect as squaring the force before multiplying it by displacement is not the correct formula for work. The correct formula for work is the product of force and displacement (W = F x d).

Correct Answer: A

Rationale: Rationale: An ideal fluid exhibits zero shear stress at any strain rate. This is because an ideal fluid is assumed to have no resistance to flow, resulting in no shear stress being generated regardless of the strain rate. This is a fundamental characteristic of an ideal fluid and distinguishes it from real fluids that exhibit varying levels of shear stress. Summary: - Choice A is correct as an ideal fluid exhibits zero shear stress at any strain rate. - Choice B is incorrect as it describes a Newtonian fluid which has a linear relationship between shear stress and strain rate. - Choice C is incorrect as it describes a Non-Newtonian fluid with a non-linear relationship between shear stress and strain rate. - Choice D is incorrect as it describes the temperature dependence of viscosity, which is not a defining characteristic of an ideal fluid.

Correct Answer: A

Rationale: To find force, we use the formula Work = Force x Distance. Given Work = 100 N⋅m and Distance = 20 m, we can rearrange the formula to find Force: Force = Work / Distance = 100 N⋅m / 20 m = 5 N. Therefore, the correct answer is A (5 N) because 5 N of force was applied to move the object. Option B (80 N) is incorrect because it does not match the calculated force of 5 N. Option C (120 N) is incorrect because it is not the result of the calculation. Option D (2,000 N) is incorrect because it is significantly higher than the calculated force of 5 N.

Correct Answer: A

Rationale: To determine the new length when the force is doubled, we can use Hooke's Law: F = kx, where F is the force, k is the spring constant, and x is the extension. First, calculate the spring constant k = F / x = 12 N / 3 cm = 4 N/cm. Then, find the new extension x' when the force is doubled (24 N): x' = F / k = 24 N / 4 N/cm = 6 cm. Therefore, the new length of the spring would be 25 cm + 6 cm = 31 cm (Choice A). The other choices are incorrect because they do not consider the linear relationship between force and extension as described by Hooke's Law.

Correct Answer: D

Rationale: Cavitation occurs when the pressure drops below the vapor pressure of the fluid, causing bubbles to form and collapse. If the pressure drops below the vapor pressure, the fluid will vaporize, leading to cavitation. Boiling point (A), density (B), and freezing point (C) are not directly related to cavitation. Boiling point is the temperature at which a liquid turns into vapor, density is the mass per unit volume of a substance, and freezing point is the temperature at which a liquid turns into a solid. Only vapor pressure (D) is directly linked to cavitation.