when a fluid encounters a bluff body eg a car the flow can separate behind the object creating a region of low pressure this phenomenon is known as
Logo

Nursing Elites

HESI A2

HESI A2 Physics Practice Test

1. When a fluid encounters a bluff body (e.g., a car), the flow can separate behind the object, creating a region of low pressure. This phenomenon is known as:

Correct answer: B

Rationale: The correct answer is B: Boundary layer separation. Boundary layer separation occurs when the flow of fluid detaches from the surface of a bluff body, leading to a low-pressure region behind the object. This separation creates a wake region with reduced pressure. Choice A, Cavitation, refers to the formation of vapor bubbles in a fluid and is not relevant in this context. Choice C, Bernoulli effect per se, does not specifically describe the phenomenon of flow separation behind a bluff body. Choice D, Drag crisis, is not the term used to describe the creation of a low-pressure region due to flow separation.

2. A pitcher throws a 45-g baseball at a velocity of 42 meters per second. What is the ball’s momentum?

Correct answer: B

Rationale: Momentum is calculated by multiplying mass (in kg) by velocity (in m/s). The mass of the baseball is 0.045 kg (45 grams converted to kg), and the velocity is 42 m/s. Momentum = 0.045 kg × 42 m/s = 1.89 kg⋅m/s. Therefore, the correct answer is 1.89 kg⋅m/s. Choice A is incorrect as it incorrectly converts the mass from grams to kg. Choice C and D are incorrect due to calculation errors.

3. A bicycle and a car are both traveling at a rate of 5 m/s. Which statement is true?

Correct answer: B

Rationale: Kinetic energy is determined by both the mass and the velocity of an object. While both the bicycle and the car are moving at the same velocity (5 m/s), the car has significantly more mass than the bicycle. As a result, the car has more kinetic energy than the bicycle, even though their speeds are identical. Therefore, choice B is correct. Choices A, C, and D are incorrect because they do not consider the influence of mass on kinetic energy. Choice A is incorrect as the car has more kinetic energy due to its greater mass. Choice C is incorrect because the vehicles have different masses. Choice D is incorrect as both the bicycle and the car possess kinetic energy.

4. A system undergoes an isobaric process (constant pressure). In this process, the work done (W) by the system is:

Correct answer: B

Rationale: In an isobaric process (constant pressure), the work done is given by the formula W = PΔV, where P is the pressure and ΔV is the change in volume. If the volume does not change, the work done is zero, not negative. Choice A is incorrect as it states the work done is zero when the volume change is zero, which is the correct condition for zero work. Choice C is incorrect as it incorrectly suggests that the work done is negative in an isobaric process. Choice D is incorrect as the work done in an isobaric process is indeed dependent on the volume change and pressure.

5. An object has a constant velocity of 50 m/s and travels for 10 s. What is the acceleration of the object?

Correct answer: A

Rationale: The acceleration of an object is defined as the rate of change of its velocity. When an object has a constant velocity, it means there is no change in its speed or direction. In this case, the object maintains a constant velocity of 50 m/s for 10 seconds, which implies that there is no change in velocity. Therefore, the acceleration of the object is 0 m/s² as there is no acceleration or deceleration happening. Choices B, C, and D are incorrect because acceleration is the change in velocity over time, and in this scenario of constant velocity, the acceleration is 0 m/s².

Similar Questions

What is the main difference between a reversible and irreversible process in thermodynamics?
When two identical charged spheres, both positively charged, are brought close together, the electrostatic force between them will be:
In a U-tube manometer, a fluid is used to measure pressure differences. When one side is connected to a pressurized system, the fluid level on that side will:
During adiabatic compression of a gas, what happens to its temperature?
When a hot cup of coffee is placed on a cold table, heat transfer primarily occurs through which process?

Access More Features

HESI A2 Basic
$49/ 30 days

  • 3,000 Questions with answers
  • 30 days access

HESI A2 Premium
$99/ 90 days

  • Actual HESI A2 Questions
  • 3,000 questions with answers
  • 90 days access

Other Courses