4.1.26 graph of velocity over acceleration graph

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Discussion Overview

The discussion revolves around plotting a velocity graph over a given piece-wise linear acceleration graph. Participants are exploring how to represent these graphs using TikZ, a LaTeX package for creating graphics. The focus includes both the graphical representation and the mathematical integration required to derive the velocity from the acceleration.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Exploratory

Main Points Raised

  • Some participants express difficulty in understanding the task of plotting the velocity graph over the acceleration graph.
  • There is a clarification that the red graph represents the velocity, which is to be plotted over the given yellow piece-wise linear acceleration graph.
  • A participant provides a TikZ code snippet to illustrate how to create the acceleration graph and suggests that the velocity graph still needs to be added.
  • One participant derives the velocity function from the acceleration function for the first segment of the graph, presenting the integration steps involved.
  • Further integration is mentioned as necessary to find the velocity for later sections of the graph.

Areas of Agreement / Disagreement

Participants generally agree on the need to plot the velocity graph over the acceleration graph, but there is no consensus on the overall approach or the completeness of the graphs being discussed. The discussion remains exploratory with multiple contributions and no final resolution.

Contextual Notes

There are unresolved aspects regarding the integration for later sections of the graph and the overall accuracy of the plotted graphs. Participants have not reached a consensus on the final representation.

karush
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View attachment 9254

ok not finding this easy but the red is mine drawn over the given book graph

also want to convert the whole thing to tikx graph
 

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karush said:
ok not finding this easy but the red is mine drawn over the given book graph

also want to convert the whole thing to tikx graph

Is the problem's given acceleration graph the piece-wise linear graph in yellow?

Why the graph in red? What's its purpose?
 
Last edited by a moderator:
yes only the red in mine

we are asked to plot velocity(red) over the given graph of acceleration
 
for the given piece-wise linear acceleration graph in yellow, the velocity graph is as shown ...
 

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karush said:
ok not finding this easy but the red is mine drawn over the given book graph

also want to convert the whole thing to tikx graph

We can do for instance:
\begin{tikzpicture}[xscale=.3, >=stealth]
\draw[ystep=0.5,help lines] (0,-2.5) grid (45,2.5);
\draw[->] (-2,0) -- (47,0) node
{(s)};
\draw[->] (0,-2.4) -- (0,2.9) node[above] {$a$ (m/s$^2$)};
\draw
foreach \i in {5,10,...,45} { (\i,0.1) -- (\i,-0.1) node[below] {$\i$} }
foreach \i in {-2,2} { (0.3,\i) -- (-0.3,\i) node
{$\i$} }
(0,0) node[below left] {$0$};
\draw[red, ultra thick]
(5,2) parabola (0,0)
(5,2) parabola (10,0)
(15,-2) parabola (10,0)
(15,-2) -- (25,-2)
(25,-2) parabola (30,0)
(35,2) parabola (30,0)
(35,2) -- (40,2)
(40,2) parabola (45,0);
\end{tikzpicture}

I guess we still need to add the velocity graph.
For the section up to 10 seconds, we have the parabola given by:
$$a(t) = 2 - \frac{2}{25}(t-5)^2 = -\frac{2}{25}t^2+\frac 45 t$$
Integrate it, to find:
$$v(t) = \int_0^t a(t)\,dt = \int_0^t \left[-\frac{2}{25}t^2+\frac 45 t\right]dt
= \left[-\frac{2}{3\cdot 25}t^3 + \frac 25 t^2\right]_0^t = -\frac{2}{75}t^3 + \frac 25 t^2$$

Putting it in a graph, we get:
\begin{tikzpicture}[xscale=.3, yscale=.3, >=stealth]
\draw[help lines] (0,-2.5) grid (45,15);
\draw[->] (-2,0) -- (47,0) node
{(s)};
\draw[->] (0,-2.4) -- (0,15.9) node[above] {$v$ (m/s)};
\draw
foreach \i in {5,10,...,45} { (\i,0.3) -- (\i,-0.3) node[below] {$\i$} }
foreach \i in {-2,5,10,15} { (0.3,\i) -- (-0.3,\i) node
{$\i$} }
(0,0) node[below left] {$0$};
\draw[cyan, ultra thick] plot[domain=0:10, variable=\t] (\t, {-(2/75)*\t^3 + (2/5)*\t^2 });
\end{tikzpicture}

Repeat to find the later sections...
And integrate again to find the x graph...​
 

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