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Pulse

Posted: Sun Jun 08, 2014 12:55 pm
by Suvekchhya
When a pulse travels towards the right of a string, why is the f(x0) = f(x' - vt) ? why is it negative?
with x0 being position at t = 0 and x' being position at t = t
Thankyou

Re: Pulse

Posted: Sun Jun 08, 2014 2:10 pm
by a.s.h.
Is it because x' = x0 + vt, so x0 = x' - vt?

Re: Pulse

Posted: Sun Jun 08, 2014 5:43 pm
by joe
Consider a point in the wave pattern, e.g. the crest of the wave. Let's put the crest at x=0 when t=0. If that crest moves to the right at v, then the x value of the crest and t increase together. f(x-vt) allows the argument to remain zero as t increases.

See the animations at
http://www.animations.physics.unsw.edu. ... ing-waves/

Joe