Math Problem Statement

A particle rotates counterclockwise in a circle of radius 4.8 m with a constant angular speed of 14 rad/s. At t = 0, the particle has an x coordinate of 0.73 m and y > 0. Determine the x coordinate of the particle at t = 2.49 s. Answer in units of meters.

Solution

To solve this problem, we will use the following steps:

  1. Determine the angular position of the particle at t=2.49st = 2.49 \, \text{s} using the angular velocity ω\omega and the initial condition.

  2. Convert the angular position into the x-coordinate of the particle, given the circle's radius and the initial position.


Step 1: Calculate the Angular Position

The angular position θ\theta is given by: θ(t)=ωt+θ0\theta(t) = \omega t + \theta_0 where:

  • ω=14rad/s\omega = 14 \, \text{rad/s} is the angular velocity,
  • t=2.49st = 2.49 \, \text{s},
  • θ0\theta_0 is the initial angular position, determined from the initial condition.

At t=0t = 0, the particle has x=0.73mx = 0.73 \, \text{m}. The relationship between xx, rr, and θ0\theta_0 is: x=rcosθ0x = r \cos \theta_0 Given r=4.8mr = 4.8 \, \text{m} and x=0.73mx = 0.73 \, \text{m}, solve for cosθ0\cos \theta_0: cosθ0=0.734.8    cosθ00.15208\cos \theta_0 = \frac{0.73}{4.8} \implies \cos \theta_0 \approx 0.15208 This gives: θ0=cos1(0.15208)1.418rad\theta_0 = \cos^{-1}(0.15208) \approx 1.418 \, \text{rad}

Now, substitute into the angular position formula: θ(t)=142.49+1.41836.276rad\theta(t) = 14 \cdot 2.49 + 1.418 \approx 36.276 \, \text{rad}

Since angular motion is periodic, reduce θ\theta modulo 2π2\pi to find the equivalent angle within one revolution: θ(t)=36.276mod2π5.497rad\theta(t) = 36.276 \mod 2\pi \approx 5.497 \, \text{rad}


Step 2: Calculate the x-coordinate

The x-coordinate is given by: x=rcosθx = r \cos \theta Substitute r=4.8mr = 4.8 \, \text{m} and θ=5.497rad\theta = 5.497 \, \text{rad}: x=4.8cos(5.497)x = 4.8 \cos(5.497)

Using trigonometric calculations: cos(5.497)0.707\cos(5.497) \approx 0.707 x4.80.7073.39mx \approx 4.8 \cdot 0.707 \approx 3.39 \, \text{m}


Final Answer:

The xx-coordinate of the particle at t=2.49st = 2.49 \, \text{s} is approximately: x3.39mx \approx 3.39 \, \text{m}


Would you like a step-by-step visualization or further clarification?

Here are 5 related questions to explore:

  1. How can we determine the y-coordinate at t=2.49st = 2.49 \, \text{s}?
  2. How does the angular velocity affect the motion of the particle?
  3. What happens if the angular velocity is not constant?
  4. Can we generalize this for elliptical motion instead of circular?
  5. How do we calculate the velocity vector of the particle at any given time?

Tip: Always reduce angles using modulo 2π2\pi for simpler calculations when dealing with circular motion!

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Angular Motion
Periodic Functions

Formulas

Angular position formula: θ(t) = ωt + θ₀
Trigonometric relationship: x = r * cos(θ)

Theorems

Cosine function in circular motion

Suitable Grade Level

Grades 10-12