What is the relationship between x-t and v-t graph?

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Homework Help Overview

The discussion revolves around the relationship between position-time (x-t), velocity-time (v-t), and acceleration-time (a-t) graphs. Participants are tasked with drawing v-t and a-t graphs based on a given x-t graph, while addressing questions of continuity and the implications of discontinuities in these graphs.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • Participants explore the implications of continuity in the x-t graph and how it affects the corresponding v-t and a-t graphs. Questions arise about the presence of discontinuities and the necessity of vertical lines in the graphs. There is also discussion about the nature of piecewise functions and the concept of differentiability.

Discussion Status

The discussion is ongoing, with participants questioning assumptions about continuity and the graphical representation of the relationships between the different types of graphs. Some guidance has been offered regarding the implications of continuity, but no consensus has been reached on the specifics of the graphs.

Contextual Notes

Participants note that the original problem does not come from a textbook, which may contribute to the ambiguity in interpreting the x-t graph's characteristics. There is a focus on understanding the principles rather than exact graphical representations.

Optikspik
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I'm suppose to draw a v-t and a-t graph from a given x-t graph.

Here is the x-t graph and my attemps on the other two graphs from the x-t one.

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Howeverr

1. My teacher said that these graphs are discontinuous? Because I often see in littetaure that they drag "a vertical line" whenever something takes a jump, but it is discontinuous in the v-t graph right?

2. If it is discontinuous, and no vertical line down, If i was given the v-t graph and wanted to do a x-t rgaph. Then I would "imagine" a vertical line right? To calculate an area ?

3. Are these 2 graphs correct or what could be improved/ Whats wrong?
 
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Tbh it's rather poorly drawn, so my answer may be off.
The position time graph appears to be a piecewise function. However, if it is mentioned in the question that it is continuous, then by default the graphs of all its derivatives (velocity-time and acceleration-time) should be continuous, so you must draw those "jump" lines.
If the last section of the x-t graph is parabolic, then the other graphs are correct.
 
Pretty crude pictures. If I look at the lower two, I wonder how v can change from something to zero with a staying at zero...
 
PWiz said:
, if it is mentioned in the question that it is continuous, then by default the graphs of all its derivatives (velocity-time and acceleration-time) should be continuous
I'd like to contradict this. A continuous function doesn't have to be continuously differentiable...
 
BvU said:
I'd like to contradict this. A continuous function doesn't have to be continuously differentiable...
That is true in general, but I have yet to see a position time graph that has an undefined gradient.
EDIT: Unless you include some of those "jumps".
 
? I don't understand what any of u talking is about. will their be a vertical line down on v-t graph or is there "space" between?

this is not a queestion from a book, and u understand when i draw, Its just the "principle" not exact. Do i think right?
 
Optikspik said:
? I don't understand what any of u talking is about. will their be a vertical line down on v-t graph or is there "space" between?
Simply put - did the question say anything at all about the continuity of the x-t graph?
 
Optikspik said:
? I don't understand what any of u talking is about. will their be a vertical line down on v-t graph or is there "space" between?

this is not a queestion from a book, and u understand when i draw, Its just the "principle" not exact. Do i think right?
Ok, fair enough. let's restart:

Homework Statement



from a given x-t graph, draw a v-t and a-t graph (top pic in post #1)
given x(t) graph does not look like top pic ? could you post it, or describe the relevant details a little better ?

Homework Equations



?​

The Attempt at a Solution


[/B]
Lower two pictures in post #1
main barrier: continuity or not ? for x? for v ? for a ?​
- - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - -

What is, according to what you have learned, the relationship between x(t) and v(t) ?

and then we'll take it from there.

--
 

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