2022 Practice Exam 2 Frq Ap Physics 1

2022 Practice Exam 2 FRQ AP Physics 1: A Comprehensive Guide

The AP Physics 1 exam is a significant hurdle for many high school students. The free-response questions (FRQs) section, in particular, can be daunting. This guide will delve into the 2022 Practice Exam 2 FRQs, providing detailed explanations, problem-solving strategies, and tips to help you master this challenging aspect of the exam. We'll break down each question, offering multiple approaches where applicable and emphasizing the crucial concepts tested. Remember, consistent practice and a deep understanding of fundamental principles are key to success.

Question 1: Kinematics and Newton's Laws

This question typically involves a scenario describing the motion of an object, often involving forces and acceleration. Let's assume a hypothetical scenario mirroring the 2022 exam's structure:

Scenario: A block of mass m slides down a frictionless incline with an angle θ to the horizontal.

(a) Draw a free-body diagram of the block.

This part tests your understanding of force diagrams. You should draw the following forces:

• Weight (mg): Acting vertically downwards. This is the force of gravity on the block.
• Normal Force (N): Acting perpendicular to the incline. This force prevents the block from falling through the surface.

(b) Determine the acceleration of the block down the incline.

This requires applying Newton's second law (F=ma). Resolve the weight vector into components parallel and perpendicular to the incline:

• Parallel component (mg sinθ): This component causes the acceleration down the incline.
• Perpendicular component (mg cosθ): This component is balanced by the normal force.

Therefore, applying Newton's second law in the direction parallel to the incline:

ma = mg sinθ

Solving for acceleration (a):

a = g sinθ

(c) If the block starts from rest and travels a distance d down the incline, find its final speed.

This part tests your knowledge of kinematics. Since the acceleration is constant, we can use the following kinematic equation:

v² = u² + 2as

Where:

• v is the final velocity
• u is the initial velocity (0 m/s since it starts from rest)
• a is the acceleration (g sinθ)
• s is the distance (d)

Solving for v:

v = √(2g d sinθ)

(d) Now, let's introduce friction. If a coefficient of kinetic friction μk exists between the block and the incline, how would this affect the acceleration?

Introducing friction adds a new force to the free-body diagram:

• Frictional force (fk): Acting parallel to the incline and opposing the motion. fk = μk N = μk mg cosθ

Now, applying Newton's second law again:

ma = mg sinθ - μk mg cosθ

Solving for acceleration:

a = g(sinθ - μk cosθ)

This shows that friction reduces the acceleration down the incline.

Question 2: Energy and Momentum

This question often involves scenarios where energy and/or momentum are conserved. Let's consider a sample problem:

Scenario: A ball of mass m is dropped from a height h above a spring with a spring constant k.

(a) What is the ball's speed just before it hits the spring?

This involves using conservation of energy. The potential energy at height h is converted into kinetic energy just before impact:

mgh = ½mv²

Solving for v:

v = √(2gh)

(b) Determine the maximum compression of the spring.

As the ball compresses the spring, kinetic energy is converted into elastic potential energy. At maximum compression, all kinetic energy is converted:

½mv² = ½kx²

Substituting the value of v from part (a):

mgh = ½kx²

Solving for x (maximum compression):

x = √(2mgh/k)

(c) If the collision between the ball and the spring is inelastic, how would this affect the maximum compression?

An inelastic collision implies that some energy is lost during the collision. If energy is lost, less energy will be available to compress the spring, resulting in a smaller maximum compression than calculated in part (b).

(d) Assume the collision is perfectly elastic. Describe the motion of the ball after it leaves the spring.

In a perfectly elastic collision, all kinetic energy is conserved. The ball will rebound upwards, reaching a height approximately equal to the initial height h, neglecting any energy losses due to air resistance.

Question 3: Circular Motion and Gravitation

This question might involve scenarios dealing with satellites, planets, or objects moving in a circular path.

Scenario: A satellite of mass m orbits a planet of mass M at a distance r from the center of the planet.

(a) Draw a free body diagram of the satellite.

The only force acting on the satellite is the gravitational force from the planet:

• Gravitational force (Fg): Acting towards the center of the planet. Fg = GMm/r²

(b) Determine the speed of the satellite.

The gravitational force provides the centripetal force required for circular motion:

GMm/r² = mv²/r

Solving for v:

v = √(GM/r)

(c) Find the period of the satellite's orbit.

The period (T) is the time taken for one complete orbit. The distance covered in one orbit is the circumference (2πr). Therefore:

v = 2πr/T

Substituting the value of v from part (b):

T = 2π√(r³/GM)

(d) If the satellite's orbit becomes elliptical, how would this affect its speed at different points in its orbit?

In an elliptical orbit, the satellite's speed varies. It moves fastest when closest to the planet (perigee) and slowest when farthest away (apogee). This is because the gravitational force and hence the centripetal force change throughout the orbit.

General Strategies for AP Physics 1 FRQs

• Read carefully: Understand the problem statement fully before starting.
• Draw diagrams: Free-body diagrams, energy diagrams, or other visual representations can significantly aid problem-solving.
• Show your work: Clearly show all steps in your calculations. Partial credit is awarded for correct steps, even if the final answer is incorrect.
• Use appropriate units: Always include units in your answers and ensure consistency.
• Check your answers: Review your work for errors and ensure your answers are reasonable.
• Practice consistently: Regular practice with past FRQs is crucial for mastering the exam format and improving your problem-solving skills.
• Understand fundamental concepts: A strong grasp of fundamental physics principles is essential. Don't rely solely on memorizing formulas; understand their derivations and applications.

This comprehensive guide provides a detailed walkthrough of potential question types within the context of the 2022 AP Physics 1 Practice Exam 2. By mastering these concepts and employing the strategies discussed, you'll significantly increase your chances of success on the actual exam. Remember, consistent practice and a clear understanding of the underlying principles are the keys to unlocking your full potential. Good luck!