# VT and DT graph help, please

1. Feb 15, 2010

### ShakeECET109

^^Exact photo copy of my quiz, let me know if its not showing up

Hi Guys, I messed up bad on a recent quiz on these easy VT and DT graphs. I am having trouble going from one to another. I recently took this quiz and pretty much got everyone wrong since then I have googled and read the chapter as much as possible, but I cant find any good completed examples to know if im doing it correctly. In our book it basically calls these things frequency polygons, histograms. Are they the same?? Is there any way to enter the x,y coordinates for a Distance time graph in my TI-89 titanium and have it output the velocity graph?? I have a test over this tomorrow and I am still a little confused

Can anyone show me the correct graphs for these 3 problems i missed on the quiz??

Thanks in advance for any info.

P.S. anyone have any good resources on how to plot derivatives on a graph ??

Last edited: Feb 15, 2010
2. Feb 15, 2010

### Fractal314

With those all I'd do is divide each section into chunks, draw a graph below it where the chunks are parallel to the new graph, and ask a question about each chunk and what would make sense to fill into the new graph.

For example, if the velocity is keeping at 10m/s the distance will rise at a slope of 10m/s. if the velocity is keeping at -10m/s the distance will fall at a slope of -10m/s.

Another example would be finding the the velocity when given the distance. So if the distance isn't changing at all (no slope) then what will the velocity be?

I guess it's just a matter of asking the right questions and converting the pictures to words where logic becomes more intuitive.

3. Feb 15, 2010

### ShakeECET109

Yeah, I get confused when "Chunking" the graphs. On the distance-time graph to velocity time. if the Distance drops -30 at 60 seconds what would the velocity bar look like? To find the velocity and represent it in a bar graph am I suppose to divide the change in distance for that "chunk" by the change in time for that "chunk".

Like if the distance drops -30 at 60 seconds, but the chunks are 20 seconds part. Do I divide -30 by the 20 second chunk? which would be represented by a bar graph that reachers 1.5 m/s on the y axis of the velocity graph?

4. Feb 15, 2010

### ShakeECET109

The velocity would be 0? I feel like i know the answer, just not why it makes sense?

5. Feb 15, 2010

### ShakeECET109

bump!

6. Feb 15, 2010

### ShakeECET109

Hi guys, I am having trouble telling the difference between Velocity-Distance,Acc-Distance and Distance-time graphs.

My teacher seems to want us to go from Velocity-distance graphs too Distance -time and vice versa, but it seems like the graphs he is talking about are acceleration.

He keeps saying that the velocity graphs we are suppose to draw wont have cruved or diagnal lines. He says they should look like bar graphs and I am really confused on how to draw a velocity graph that represents the graphs on the quiz