### 5. Class 11th Physics | Waves Motion | Propagation of a Progressive Wave Pulse | by Ashish Arora

- by
**Garret Jacobs** - 3 months ago
- 11 comments

let's discuss the propagation of a progressive

wave pulse , say we are given with a stretched string , along x axis , and say a wave pulse

is generated. at a time, t is equal to zero, which is having

, the shape, y is equal to f of x , this y is equal to f of x can be written as, the

equation of displacement of this wave pulse , which is travelling, say in the positive

x direction, at speed v , obviously at time t ,the wave will travel, a distance vt, and

it will keep the shape same . as we have studied that the phase of oscillating

particle will remain , unchanged s , as the wave propagates , or along with the wave propagation

phase also propagates , along with the shape and we can say the shape, is representing

the phase of particle at any instant . when a pulse is created at t equal to zero having,

the equation of displacement curve as y is equal to f of x .

and it is travelling at a speed v , then at time t it will be a position vt so if we talk

about , its shape after time t , we can write as after time t , equation of, displacement

curve . of the wave pulse , will be given as , here it be given as y is equal to f of

, x minus vt , because it has travelled a distance vt, so origin is vt distance displaced

behind, the wave pulse . so here we can say , the shape will remain

same, but the position coordinates of the pulse, are shifted by position vt , so if

it travelling in the positive direction of the x axis we can write its equation to be,

f of x minus vt , and if the wave is travelling in the negative direction of the x axis we

will write , it as, f of x plus vt, so be careful because some different types of numerical

we will discuss , which will be based on , the shape displacement curve of a wave pulse .

Sir please elaborate the basic concept in video

Plz reply to my query Sir.

Sir, i also did not understand how origin is dispaced vt distance behind the wave pulse , please explain sir.

Sir, have you used shifting of origin

Concept

Sir how did the expression f(x-vt) come? You said origin is vt distance behind the wave pulse… what does that mean? Please reply

In negative x-axis, we mean oscillator stops and wave pulse loses energy. please clarify sir

Sir, displacement y gives idea about its amplitude and phase? Please clarify

Allen coaching?

oh. now I understand. TY sir.

Plz reply sir

Sir. I dint understand this point. Why is y=f(x-vt). Isn't x and vt same.