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Ch 04: Kinematics in Two Dimensions
Chapter 4, Problem 8

CALC A 100 g bead slides along a frictionless wire with the parabolic shape y = (2m⁻¹) x^2. a. Find an expression for aᵧ, the vertical component of acceleration, in terms of x, vₓ, and aₓ. Hint: Use the basic definitions of velocity and acceleration.

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Identify the relationship between the position, velocity, and acceleration in the x-direction and y-direction. Since the wire has a parabolic shape given by y = (2m⁻¹) x^2, differentiate this equation with respect to time to find the velocity in the y-direction (vᵧ) in terms of the velocity in the x-direction (vₓ). Use the chain rule: vᵧ = dy/dt = (dy/dx) * (dx/dt) = 4x * vₓ.
Differentiate the expression for vᵧ again with respect to time to find the acceleration in the y-direction (aᵧ). Use the chain rule and product rule: aᵧ = dvᵧ/dt = d/dt (4x * vₓ) = 4 * (dx/dt) * vₓ + 4x * (dvₓ/dt) = 4vₓ^2 + 4xaₓ.
Simplify the expression for aᵧ to express it in terms of x, vₓ, and aₓ. From the previous step, we have aᵧ = 4vₓ^2 + 4xaₓ.
Verify the units of each term in the expression for aᵧ to ensure consistency. The units of acceleration (m/s²) should be the same on both sides of the equation.
Interpret the physical meaning of each term in the expression for aᵧ. The term 4vₓ^2 represents the component of acceleration due to the change in speed along the curve, while 4xaₓ represents the component of acceleration due to the curvature of the path.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Acceleration

Acceleration is the rate of change of velocity with respect to time. In this context, it can be broken down into components, such as the vertical component (aᵧ) and the horizontal component (aₓ). Understanding how to express acceleration in terms of position and velocity is crucial for analyzing motion along a curved path.
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Velocity Components

Velocity can be decomposed into its components along different axes, typically horizontal (vₓ) and vertical (vᵧ). For a particle moving along a curve, the total velocity is influenced by both components, and their relationship is essential for deriving expressions for acceleration. This concept is fundamental when applying calculus to motion in two dimensions.
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Curvilinear Motion

Curvilinear motion refers to the motion of an object along a curved path. In this case, the bead moves along a parabolic wire, which requires the use of parametric equations to describe its position and motion. Understanding the geometry of the path and how it affects the forces and accelerations acting on the object is key to solving the problem.
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