Table of contents
- 0. Math Review31m
- 1. Intro to Physics Units1h 26m
- 2. 1D Motion / Kinematics3h 56m
- Vectors, Scalars, & Displacement13m
- Average Velocity32m
- Intro to Acceleration7m
- Position-Time Graphs & Velocity26m
- Conceptual Problems with Position-Time Graphs22m
- Velocity-Time Graphs & Acceleration5m
- Calculating Displacement from Velocity-Time Graphs15m
- Conceptual Problems with Velocity-Time Graphs10m
- Calculating Change in Velocity from Acceleration-Time Graphs10m
- Graphing Position, Velocity, and Acceleration Graphs11m
- Kinematics Equations37m
- Vertical Motion and Free Fall19m
- Catch/Overtake Problems23m
- 3. Vectors2h 43m
- Review of Vectors vs. Scalars1m
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- Calculating Dot Product Using Components12m
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- 4. 2D Kinematics1h 42m
- 5. Projectile Motion3h 6m
- 6. Intro to Forces (Dynamics)3h 22m
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- Uniform Circular Motion7m
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- Magnetic Field Produced by Loops andSolenoids42m
- Toroidal Solenoids aka Toroids12m
- Biot-Savart Law (Calculus)18m
- Ampere's Law (Calculus)17m
- 30. Induction and Inductance3h 37m
- 31. Alternating Current2h 37m
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- Series LRC Circuits11m
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- Power in AC Circuits5m
- 32. Electromagnetic Waves2h 14m
- 33. Geometric Optics2h 57m
- 34. Wave Optics1h 15m
- 35. Special Relativity2h 10m
4. 2D Kinematics
Intro to Motion in 2D: Position & Displacement
Problem 3.7a
Textbook Question
The coordinates of a bird flying in the xy-plane are given by x(t) = αt and y(t) = 3.0 m − βt2, where α = 2.4 m/s and β = 1.2 m/s2. (a) Sketch the path of the bird between t = 0 and t = 2.0 s.

1
Understand the equations of motion: The bird's position in the xy-plane is described by two equations: x(t) = αt and y(t) = 3.0 m − βt², where α = 2.4 m/s and β = 1.2 m/s². These equations give the x and y coordinates of the bird at any time t.
Determine the range of time: We need to sketch the path of the bird between t = 0 and t = 2.0 s. This means we will calculate the bird's position at several points within this time interval.
Calculate the x and y coordinates at key time points: Start by calculating the coordinates at t = 0, t = 1.0 s, and t = 2.0 s. For example, at t = 0, x(0) = α * 0 = 0 and y(0) = 3.0 m − β * 0² = 3.0 m. Repeat this for t = 1.0 s and t = 2.0 s.
Plot the points on the xy-plane: Using the coordinates calculated, plot the points on a graph with the x-axis representing x(t) and the y-axis representing y(t). Connect these points to visualize the path of the bird.
Analyze the path: Observe the shape of the path. The x-coordinate increases linearly with time, while the y-coordinate decreases quadratically, indicating the bird is moving forward while descending in a parabolic trajectory.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Parametric Equations
Parametric equations express the coordinates of a point in terms of a parameter, often time. In this problem, x(t) = αt and y(t) = 3.0 m − βt² describe the bird's position as functions of time, allowing us to determine its trajectory in the xy-plane by varying t.
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Projectile Motion
Projectile motion involves objects moving in two dimensions under the influence of gravity. The bird's y-coordinate follows a quadratic equation, typical of vertical motion under constant acceleration, while the x-coordinate changes linearly, indicating uniform horizontal motion.
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Graphing Techniques
Graphing techniques are essential for visualizing mathematical relationships. To sketch the bird's path, plot x(t) and y(t) for values of t from 0 to 2.0 s, showing how the bird's position changes over time, and illustrating the combined effects of linear and quadratic motion.
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Graphing Position, Velocity, and Acceleration Graphs
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