My Math Forum  

Go Back   My Math Forum > High School Math Forum > Geometry

Geometry Geometry Math Forum


Thanks Tree2Thanks
  • 2 Post By skipjack
Reply
 
LinkBack Thread Tools Display Modes
June 10th, 2019, 10:06 AM   #1
Member
 
Joined: Aug 2017
From: India

Posts: 54
Thanks: 2

Phasor Representation of sine wave

I don't understand why Sine wave should be represented as a phasor, that is, as a circle with a rotating vector. Why should it be rotating at angular speed (omega)? This is an additional item that confuses me. Suppose in the picture I am assuming it is moving at some speed; if it runs at twice the speed, how does the waveform will look like? I know the questions are not clear, but how I do I link omega, t, frequency?
Attached Images
File Type: jpg Sine.jpg (12.0 KB, 8 views)

Last edited by skipjack; June 11th, 2019 at 04:28 AM.
MathsLearner123 is offline  
 
June 11th, 2019, 04:40 AM   #2
Global Moderator
 
Joined: Dec 2006

Posts: 20,966
Thanks: 2216

The sine wave doesn't need to be related to a rotating vector. Although the diagram refers to the time domain, the horizontal axis for the sine wave uses ωt, which is dimensionless and corresponds to an angle in the left-hand diagram (if ω isn't zero).

The word "frequency" relates to how often something occurs. If you choose to consider a vector that rotates at a constant non-zero rate, it's convenient to draw a horizontal axis that aligns with the vector at time zero. If that alignment occurs n times per second, it would be reasonable to refer to "n times per second" as the frequency of the rotation. After t seconds have elapsed, the vector has rotated through 2$\pi$n radians, so ω = 2$\pi$n.

You asked how the waveform looks if the frequency is changed. What the waveform "looks like" depends on the scaling used for drawing it. If the frequency is changed and a corresponding change is made to the scaling, the waveform will look the same.
Thanks from topsquark and MathsLearner123
skipjack is offline  
June 11th, 2019, 07:38 AM   #3
Member
 
Joined: Aug 2017
From: India

Posts: 54
Thanks: 2

Quote:
Originally Posted by skipjack View Post
After t seconds have elapsed, the vector has rotated through 2$\pi$n radians, so ω = 2$\pi$n.
Will it be 2$\pi$nt?
MathsLearner123 is offline  
Reply

  My Math Forum > High School Math Forum > Geometry

Tags
phasor, representation, sine, wave



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
sine wave and sin function MMath Trigonometry 2 May 21st, 2016 07:13 AM
Linearization of sine wave HypoXic5665 Applied Math 1 April 2nd, 2013 11:39 PM
parametrization of sine wave deedee Trigonometry 6 January 21st, 2013 09:33 AM
sine wave problem smash Trigonometry 9 January 4th, 2011 05:29 PM
Need a 2D Sine wave blazingclaymore Computer Science 0 February 5th, 2008 01:01 PM





Copyright © 2019 My Math Forum. All rights reserved.