How is a negative pulse reflected from a free end
LESSON 11 - PULSE AT FREE AND FIXED ENDS BOUNDARY
this lesson is about post reflection from fixed and free ends learning
objectives compare and contrast a single post reflection from a fixed and lose
ends use animation to explain the shape of a reflected post at the boundary
identify interferences between two pulses traveling in the same median in
practice pulse interference using pH 18 wave on a string visual web let us
consider what happens to a post when it reaches the end of the median the median
can be fixed like a rope tied to a wall or it can be free like a rope tied
loosely to a pole when the end of the medium is fixed this pulse will reflect
from the free end inverted when the end of the median is free this pulse will
reflect from the free end but not inverted the fix and three ends are
examples of boundary conditions the shape of a reflected pulse for a fixed
and end for a free end of boundary conditions is affected by chill and
detected pulses they are reflected pulse the propagates through the median and
the undisturbed posts isn't East I'll explain this using this online
simulation with animation the idea about this animation is to observe the
behavior of a post when hits a boundary for two situations a free end and a
fixed and I will explain the results of this animation in terms of wave
interference a post is half of a wave sometimes is useful to use a pose
instead of a complete wave to observe waves properties to keep simple let me
explain parts of this animation in practical ways for a better
understanding this pink line is a string with one end attached to a boundary for
two ways one is a fixed end and the other one is a free end like the string
attached to a ring around a pole and free to move let me start by selecting
the fix and and around this animation
this is the incident pulse moving to the right and this is the reflected pulse
moving to the left we notice the reflected pulse restore its shapes after
hits the boundary and bounce back to the median with the same shape and with the
same speed but invert it to understand this behavior let's select the box to
show they are reflected incident pulse and as you notice this pulse is being
transmitted to the median now let's check the box show undisturbed reflected
this blue one it shows their own reflected posts the blue overlapping
with the transmitted force which is the red as they meet the boundary during
this overlapping destructive interference of course then as both
pulses move away the reflected pulse is restored and returns to the median
imported now let's uncheck all these boxes select the free end reset this
animation and run one more time we observe the incident posts amplitudes
double IDI hits the boundary then restored to its original amplitude and
returns to the median to understand this behavior let's again select the box to
show a reflected incident posts we notice the wave is me transmitted to the
median now let me check the box show undisturbed reflected posts
it shows the blue posts overlapping with the red posts both waves overlap here at
the boundary here occurs constructive interference as a result of the incident
post amplitude is double and as the blue and red pulses move away the amplitude
is restore to its original shape the also returns to the media in
conclusion for the fixed end and the boundary comes destructive interference
occurs in the reflected pulse Ritu restores its original size as it returns
to the medium averted for the free end constructor interference occurs at the
boundary and the reflected pulse restored should it's normal amplitude
have returned to the medium now then two pulses pass through the same median at
the same time they interact the resulting pulse is obtained by using
constructive interference or destructive interference the issue is also called
superposition after pulses pass through each other each pulse continues along
its original direction of travel and the original amplitudes remain unchanged the
next video I will do a practice pulse interference using pH ET wave on a
string visual level there is wave on a string simulation we are using fixed in
loose ends subserve constructive and destructive interference between two
pulses traveling for the same medium in this case a string to conduct this
practice select pulse for amplitude is light up to 1.25 for pulse width select
0.25 seconds non damping high tension these settings
provide a better view of this interaction first let's observe the
behavior of a single pose traveling through this string notice
this end is fixed at the post generator and at this end
I can select fixed or lose and click on these green buttons and create a posts
let's run with a normal speed now let's select a slow-motion let's stop and use
the time frame to observe with more detail how the post is traveling this is
great review interference with more details click on restart and select lose
and create a post and let's observe in slow-motion so watch the video post in
this lesson post a reflection free and fix ends to understand the shape of
these reflected posts so let's click on restart now let's select fix and and
create two consecutive pulses and observe in slow motion its interference
one two
so we notice sections of destructive interference so for a closer look
let's use the time frame to observe the sequence how it of course let's select a
timer and let's recall the time it takes for five destructive interference occurs
in this case one two three four five so about five point six to seven seconds
takes for five destructive interference of course
so now let's restart and select loose and reset the timer and the create show
pulses and observe its interference one two so we can observe
destructive and constructive interference
this is constructive interference
destructive interference here and
constructive interference so we have positive constructive interference on
the positive side negative constructive interference and that we have
destructive interference so we can to make a sample we can count the time it
takes for five interference of course
one two three four five in conclusion you can use this animation to create two
pulses for one of those two situation fix or lose ends and observe wave
interference constructive and destructive interference
