How Do You Analyze Acceleration on a Position vs. Time Graph?

In summary: Yeah no problem! Can you help me on my post? :)Welcome to the forum! Can you help me with my post? :)
  • #1
omc1
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0

Homework Statement


A plot of Calvin's Mom's position vs. time is shown. Rank the acceleration of the five regions (e.g., A, B, etc.) from most negative to most positive

See attachment!

Homework Equations





The Attempt at a Solution

I think that b is the most negative and c is zero, a is increasing acceleration but I just don't understand how to read this graph. Please help my final is tomorrow! thanks
 

Attachments

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  • #2
omc1 said:

Homework Statement


A plot of Calvin's Mom's position vs. time is shown. Rank the acceleration of the five regions (e.g., A, B, etc.) from most negative to most positive

See attachment!

Homework Equations



The Attempt at a Solution

I think that b is the most negative and c is zero, a is increasing acceleration but I just don't understand how to read this graph. Please help my final is tomorrow! thanks

attachment.php?attachmentid=54008&d=1355760371.gif


This is position vs. time, so the derivative (slope at any point) of this graph gives the velocity.

The rate of change of the velocity is the acceleration.

So, on this graph:
Where is the slope increasing?

Where is the slope decreasing?

Where is the slope constant?​
 
  • #3
well, the slope is increasing at a, and maybe at e, its constant at c, and decreasing at d, then at b it is slowing down
 
  • #4
Is the slope (not the function itself) really decreasing in D?
The other parts are right.
 
  • #5
well at first i thought d was constant and since slope relates to the velocity then a is zero but iam just really confused when trying to read this graph
 
  • #6
Your first thought was right. D corresponds to a constant, negative velocity. No acceleration there.
 
  • #7
ok that makes sense, thanks!
 
  • #8
Bumping an old thread for a little help on a similar question.

I am given a position vs time graph:
p1singrflow.gif


I am asked where acceleration is positive and where it is negative.

I believe I understand that when the slope of the line is increasing then the acceleration is positive. When the slope of the line is decreasing then the acceleration should be negative. Correct?

So from what I see here acceleration at the given points should be:
A - Negative
B - 0
C - Negative
D - Positive
E - 0
F - Positive

Yet these answers are being marked as incorrect when I submit them. Can PF lend me a hand here? Thank you!
 
  • #9
th3c00n said:
Bumping an old thread for a little help on a similar question.

I am given a position vs time graph:
p1singrflow.gif


I am asked where acceleration is positive and where it is negative.

I believe I understand that when the slope of the line is increasing then the acceleration is positive. When the slope of the line is decreasing then the acceleration should be negative. Correct?

So from what I see here acceleration at the given points should be:
A - Negative
B - 0
C - Negative
D - Positive
E - 0
F - Positive

Yet these answers are being marked as incorrect when I submit them. Can PF lend me a hand here? Thank you!

I think B and E are incorrect.

Curvature upward acceleration is positive and curvature downward acceleration is negative.
 
  • #10
B and E appear to be where the object changes direction. An earlier part of the question asked where velocity was 0 and those were the correct answers. Can you have acceleration without velocity?
 
  • #11
Apparently you can, that was the correct answer, thank you!
 
  • #12
th3c00n said:
B and E appear to be where the object changes direction. An earlier part of the question asked where velocity was 0 and those were the correct answers. Can you have acceleration without velocity?

Well I thought that you were looking for acceleration.
 
  • #13
th3c00n said:
Apparently you can, that was the correct answer, thank you!

Yo if the graph is position vs time then velocity would be zero when the slope is zero but if they ask for acceleration then its different. (refer back to my original post).
 
  • #14


Toranc3 said:
Yo if the graph is position vs time then velocity would be zero when the slope is zero but if they ask for acceleration then its different. (refer back to my original post).

Yep, got it now. I guess I wasn't thinking of local min/max points as a change in slope. Not sure why... Ha. Thank you again!
 
  • #15
th3c00n said:
Yep, got it now. I guess I wasn't thinking of local min/max points as a change in slope. Not sure why... Ha. Thank you again!

Yeah no problem! Can you help me on my post? :)
 
  • #16
th3c00n said:
Bumping an old thread for a little help on a similar question.

I am given a position vs time graph:
p1singrflow.gif

...
I see that you're new to PF, so Welcome!

I should point out that according to the rules of this forum, you should have started a new thread to post this rather than "highjacking" an existing thread.
 

FAQ: How Do You Analyze Acceleration on a Position vs. Time Graph?

What is a position versus time graph?

A position versus time graph is a visual representation of the position of an object over time. It shows how the position of the object changes as time passes.

How do you interpret a position versus time graph?

To interpret a position versus time graph, you can look at the slope of the line. A steeper slope indicates a faster rate of change in position, while a flatter slope indicates a slower rate of change. The position of the object can also be determined by looking at the y-axis, while the time can be determined by looking at the x-axis.

What can a position versus time graph tell us about an object's motion?

A position versus time graph can tell us about an object's speed and direction of motion. A steep slope indicates a high speed, while a flat slope indicates a low speed. The direction of the slope also indicates the direction of motion, with a positive slope indicating motion in one direction and a negative slope indicating motion in the opposite direction.

How is a position versus time graph different from a velocity versus time graph?

A position versus time graph shows the position of an object at different points in time, while a velocity versus time graph shows the velocity or speed of an object at different points in time. The slope of a position versus time graph gives the velocity, while the slope of a velocity versus time graph gives the acceleration of the object.

Can a position versus time graph be used to predict future motion?

Yes, a position versus time graph can be used to predict future motion by looking at the trend of the graph. If the graph continues in a straight line, the object will continue to move at a constant speed. However, if the graph starts to curve, it indicates a change in speed or direction of the object's motion.

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