Finding Trajectory of x & y in Kinematics

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Homework Help Overview

The discussion revolves around finding the trajectory described by the parametric equations for x and y in a kinematics context. The equations provided are x = 4cos(2t) + 3sin(2t) and y = 3cos(2t) - 4sin(2t.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants explore the periodic nature of the trajectory and question how often it repeats. There are attempts to understand the implications of the equations and the relationship between x and y. Some participants suggest plotting values against time to visualize the trajectory.

Discussion Status

There is an ongoing exploration of the periodicity of the trajectory, with some participants providing insights into the mathematical properties of sine and cosine functions. References to external resources and translations indicate a collaborative effort to clarify the task requirements.

Contextual Notes

Participants mention a specific task from a Serbian document, which includes additional requirements such as determining velocity and acceleration at a specific time. There is a noted challenge in understanding the task due to language barriers and the complexity of the equations involved.

Kitanov
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Thread moved from a technical forum, yada, yada... :-)
I need to find a trajectory

x = 4cos(2t) + 3sin(2t)
y = 3cos(2t) - 4sin(2t)
 
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Kitanov said:
I need to find a trajectory
Will it repeat?
How often?
 
Baluncore said:
Will it repeat?
How often?

I don't know what you think will happen again.
That's the whole task, there is no explanation of how the task is done. I can send you where that task is from, but you won't understand anything because it's in Serbian.

http://www.tfzr.uns.ac.rs/Content/files/0/Kinematika - I deo.pdf
Task 2
 
The trajectory is a function of 2t.
Sine and cosine repeat evert 2π, so the trajectory will repeat. What period?
Plot values of x and y against t.
 
Serbian is easy with google translate...
Page 6 of the .pdf
The question and a solution is presented on that page. I translate, but not all the equations.

Zadatak 2: Kretanje tačke određeno je jednačinama =
Task 2: The motion of a point is determined by equations

𝑥=4cos(2𝑡)+3sin(2𝑡)
𝑦=3cos(2𝑡)−4sin(2𝑡)
(𝑥, 𝑦 - in meters, 𝑡 - in seconds)

Odrediti trajektoriju (putanju), brzinu i ubrzanje tačke u trenutku kada je 𝑡=𝜋[𝑠]
= Determine the trajectory (trajectory), velocity and acceleration of a point at the moment when 𝑡 = 𝜋[𝑠]

Rešenje: = Solution:
Trajektorija (putanja) = Trajectory (path)
Dobijene jednačine kvadrirati i sabrati = Square and add the obtained equations
Brzina = Speed.
Ubrzanje = Acceleration.
 
Baluncore said:
Serbian is easy with google translate...
Page 6 of the .pdf
The question and a solution is presented on that page. I translate, but not all the equations.

Zadatak 2: Kretanje tačke određeno je jednačinama =
Task 2: The motion of a point is determined by equations

𝑥=4cos(2𝑡)+3sin(2𝑡)
𝑦=3cos(2𝑡)−4sin(2𝑡)
(𝑥, 𝑦 - in meters, 𝑡 - in seconds)

Odrediti trajektoriju (putanju), brzinu i ubrzanje tačke u trenutku kada je 𝑡=𝜋[𝑠]
= Determine the trajectory (trajectory), velocity and acceleration of a point at the moment when 𝑡 = 𝜋[𝑠]

Rešenje: = Solution:
Trajektorija (putanja) = Trajectory (path)
Dobijene jednačine kvadrirati i sabrati = Square and add the obtained equations
Brzina = Speed.
Ubrzanje = Acceleration.

I speak Serbian. I understand what is written there, but it was not clear to me why it is done that way.
Now it is.
 
Kitanov said:
I need to find a trajectory

x = 4cos(2t) + 3sin(2t)
y = 3cos(2t) - 4sin(2t)
express ##\cos 2t## and ##\sin 2t## and use ##\cos^2+\sin^2=1##
 
Last edited:

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