From @JohnDenker: A question about figure 16.3 on page 402:
-- Is this real video of real beads on a real string ...
-- or is it an animation of fake beads on an ideal string?
The first time I read this passage, I assumed it was real video
with a little bit of highlighting, and there's nothing in the
text to suggest otherwise, but the more I look at it the more
I suspect it's an animation of a not-very-realistic model
system.
This affects the physics in nontrivial ways. In particular,
the «video» is being used to prove things that aren't true,
such as the claim later on page 402 that "The wave speed c
of a wave pulse along a string is constant." In real life,
in many cases that is not true, including (among others!)
cases where the dy/dx of the wave is not small. The dy/dx
in figure 16.3 is large enough that I would expect to see
significant nonlinearity.
From @JohnDenker: A question about figure 16.3 on page 402: -- Is this real video of real beads on a real string ... -- or is it an animation of fake beads on an ideal string?
The first time I read this passage, I assumed it was real video with a little bit of highlighting, and there's nothing in the text to suggest otherwise, but the more I look at it the more I suspect it's an animation of a not-very-realistic model system.
This affects the physics in nontrivial ways. In particular, the «video» is being used to prove things that aren't true, such as the claim later on page 402 that "The wave speed c of a wave pulse along a string is constant." In real life, in many cases that is not true, including (among others!) cases where the dy/dx of the wave is not small. The dy/dx in figure 16.3 is large enough that I would expect to see significant nonlinearity.
Am I misunderstanding something here?