# History and Snapshot Graphs

1. Feb 1, 2017

### riceking95

1. The problem statement, all variables and given/known data
Number 6:
For this problem I'm changing the wave speed to 3.0 m/s instead of 1 m/s because that's what our teacher instructed us to do.
2. Relevant equations
None that I know of

3. The attempt at a solution
I'm having the hardest time making connections between the graphs and more specifically converting one graph to the other. I understand that the snapshot graph represents the displacement of the wave as a function of x and make the analogy of "the experience" a particle will go through. Also I know that the history graph shows what is happening to the medium at the specific point. But when it comes to graphs that are a bit more complex than easier x positions and different velocities I lose track of what's going on.

With this problem it says it is a history graph at x=2m with the wave moving at 3 m/s. Knowing this I would say that for the snapshot, the 2m will be affected immediately by the wave because of the placement of the leading edge on the history graph.
I also recognized from my teacher's solution that each second that's hashed on the graph is equivalent to the 3 meters which is understandable, but I really can't connect with what's going on overall. Any help would be greatly appreciated, thank you.

Here's my teacher's solution:

2. Feb 1, 2017

### BvU

Hello Riceking,

Well, you got most of it!
From the figure in the book you saw x=2 starts going up at t=0 and is back to 0 at t=4, so the whole snapshot "up from zero" width must be 12 m.
Similarly: x=2 is at its peak at t=1, so the rising flank of the wave is 3 m wide. With the 1 cm amplitude, that's enough to draw teacher's picture.
Change from 1 m/s to 3 m/s was probably introduced by teacher becasue 1 m/s is almost too easy (either that, or he doesn't want to see tiny drawings being handed in )