Home » Ask & Discuss » Physics. » Mechanics « Back to Discussion

Mechanics

Scorching goIITian

Joined:	16 Jan 2009
Post:	252

8 May 2009 18:18:03 IST

0 People liked this

277

Longitudinal waves question

Kinematics , NewtonsLawsCirMotion , Work Power Energy collisions , Rotation , Gravitation , Simple Harmonic Motion , Fluid Mechanics , Materials Wave Sound , Super Position , units dimensions , com momentum , shm , wave sound

A longitutidinal wave has equation x=x0sin(wt-kx) (w=omega) x0=x nought

What is its wave veloctiy?

My question is that when we do dx/dt dont v have to differentiate the x in the sine term as well?

Share this article on:

Comments (2)

apollo

Blazing goIITian

Joined: 21 Mar 2009

Posts: 345

8 May 2009 18:19:14 IST

Like 0 people liked this

yes we have to do that

Akshay

Blazing goIITian

Joined: 27 Dec 2007

Posts: 689

8 May 2009 18:23:38 IST

Like 1 people liked this

????

when you differentiate for wave velocity, u differentiate only the argument inside the sine term.

this argument remains constant....

therefore wt-kx=fixed (points on the waveform retain their displacement)

so w-kdx/dt=0

hence dx/dt=wave velocity=w/k

note that this argument remains constant for any point on the wave form and not points in the medium itself...

ur nomenclature itself is confusing.

although displacement of the particles and waves are parallel, the x's on LHS and RHS are different

so it is better to denote the particle displacement on the LHS by some other variable..

Quick Reply

Reply

	Some HTML allowed.
	Keep your comments above the belt or risk having them deleted.
	Signup for a avatar to have your pictures show up by your comment
	If Members see a thread that violates the Posting Rules, bring it to the attention of the Moderator Team