Velocity, position, acceleration graph help

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Discussion Overview

The discussion revolves around a physics problem related to interpreting a velocity/time graph to determine the distance traveled by an object and the necessary information to find its position at a specific time. The scope includes conceptual understanding and mathematical reasoning related to graph interpretation.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Conceptual clarification

Main Points Raised

  • One participant expresses difficulty with a velocity/time graph problem, specifically asking how to determine the distance moved by an object and what additional information is needed to find its position at a given time.
  • Another participant suggests that the area under the velocity/time graph represents the distance traveled and recommends breaking the area into simple geometric shapes for calculation.
  • A different participant raises a concern about the graph being curved, complicating the area calculation, and inquires if there is a specific method or formula for finding the area of the irregular shape.
  • One participant advises dividing the irregular shape into smaller measurable sections to calculate the area more accurately, emphasizing that the accuracy depends on the size of the time interval chosen.
  • Clarification is provided regarding a potential typo in the original question about the time interval, confirming it should be 0.4 seconds instead of 4 seconds.
  • In response to the second part of the question, a participant states that knowing the distance traveled and the initial position is necessary to determine the final position, assuming straight-line motion during the interval.

Areas of Agreement / Disagreement

Participants generally agree on the method of calculating distance using the area under the graph, but there is uncertainty regarding how to handle the irregular shape of the graph. The second part of the question about determining position has not been fully addressed, indicating a lack of consensus on that aspect.

Contextual Notes

Participants have not resolved the specifics of calculating the area under a curved graph, and there may be assumptions regarding the nature of the motion (e.g., straight-line motion) that are not explicitly stated.

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im new to this site...so i don't kno whow this works...ANYWAYS...

so you guys know : I am 16, taking a college course at mt sac (physics 1)...and I am kind of struggling because my math isn't as high as it nees to be for the coruse and because i don't understand soem concepts.

im having trouble with a velocity/time graph problem... the question asks me to determine the distance moved by the object in the time interval from t=0 to t=0.4 (since u guys can't see the graph, i will tell u...the velocity moves from 3.4 to 3.9 in 4 seconds) anyone know how to do this?

the second part to this problem is What additional information do you need to determine the position of the object at t=0.4 s? explain.

CAN ANYONE HELP ME WITH THIS? Thanks guys! (and if you are a girl, girls) :wink:
 
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There are two ways of doing this but you want to do it the graph way. The most important thing to remember is that the area under a velocity/time graph is equal to the distance travelled. So isolate the area under the graph from said interval and divide it up into simple shapes - squares/triangles. It's just very easy geometry from there.

For the second half I'm not sure what they mean by that.
 
Last edited:
thanks for the advice! :) it helped a littel bit...but the problem i have is that the graph is curved...and makes a triangle and an almost-full rectangle...but not an actual one...so how would i find the area of the weird shape? is there a secret way or formula? :confused:

and can anyon eelse help me with part 2? :confused:


thanx :smile:
 
I think Mr peanut already said this , if you must do it graphically ( and the shape is not a rectangle - then you divide the shape into small but measureable sections. Typically use a given small section of time say 0.1 seconds and divide the x-axis ( time ) into a number of the sections.In each section measure the y value ( velocity) -- the strip area is thus v*dt . Add up all the sections to get the total area the result is the distance.The accuracy is dependent on the size of dt chosen.
Do you have a typo in the question you said the velocity changes from 3.4 to 3.9 in '4' seconds . did you mean 0.4.
 
yes, i meant 0.4...thanx for ur help...does anyone else know anything about this particular question?


and can ANYONE answer part 2? :confused: :frown:
 
Part 2:
Assuming you know the distance traveled in the time interval, you'll also need the initial position in order to determine the final position
(I assumed that during the time interval the particle moved in a straight line from the initial position)
 

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