How Do You Calculate Speed and Uncertainty with Given Measurements?

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Homework Help Overview

The discussion revolves around calculating the speed of a moving object while considering uncertainties in measurements. The original poster presents a scenario involving multiple trials to determine speed and expresses frustration over inconsistent results.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to apply the formula for speed and incorporates uncertainties in distance and time. They question the accuracy of their calculations and seek clarification on how to properly account for uncertainties.

Discussion Status

Participants are engaged in exploring the problem, with the original poster expressing a need for assistance. Some participants have provided external resources, indicating a willingness to help, but there is no clear consensus or resolution yet.

Contextual Notes

The original poster mentions conducting 15 trials and obtaining varying speed results, which raises questions about the reliability of their measurements and the method of calculating uncertainties. They also highlight the specific uncertainties associated with their measurements.

Alipepsi
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Homework Statement


Hey there, I need some help with uncertainties and how to find the speed of a moving object. I have tried to solve the problem several times but my answer seems to be wrong.

Formula for speed : v=d/t
My uncertainties: 0.5cm (distance) and 0.5s for time. The uncertainties were measured with the same analog.
I did the experiment 15 times and got different speed result of the object each time. The total sum of the speeds ( 15 trials) was 44.99s. The average of that is 2.99 (15/44.99)
Oh and my measuring device was 228cm long (exact)

I need to find out the speed and the uncertainties
If I missed any detail please please let me know
PLEASE HELP! I'am very frustrated right now..=S


Homework Equations



Formula to use : v=d/t

The Attempt at a Solution



v=d/t
= (228 +\- 0.5)m/(2.99+\- 0.5)s
228 divided by 0.5 = 456%
2.99 divided by 0.5= 5.78%
456% +5.78%=461.98%

so now 461.98% * 76.2 ( which I got by diving 288 and 2.99)
my final answer was v=76.25m? +\- 39%..
I'am confused..
 
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Actually spend hours on trying to solve this :S
Help will be greatly appreciated!
 
anyone?
 
Check out this site here: http://www.rit.edu/cos/uphysics/uncertainties/Uncertaintiespart2.html
 
Last edited by a moderator:
Okey, thanks
 

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