Error calculation for moment of inertia

In summary: Your name]In summary, the forum user shared their experiment and calculations for determining the error in their results. However, there were a few errors in their calculations, which affected the final result. After corrections were made, the total error was found to be 0.006, or approximately 0.6%. The forum user was advised to use the correct value for the acceleration due to gravity and the formula for combining relative errors.
  • #1
lydiazmi
6
0

Homework Statement


I did an experiment, n now I hv to calculate the error.

Homework Equations


This equation is given: mR^2((gt^2/2h)-1)


The Attempt at a Solution


I found out that

t=1.658s
delta t=0.094s
h=0.31m
delta h=0.5*10^-3m
m=0.5456kg
delta m=0.5*10^-4kg
R=5.4*10^-3m
delta R=5.1*10^-4m
g=9.806m/c^2
delta g=0.006m/c^2

d I= square root of ((delta m/m)^2+4(delta R/R)^2+(delta g*t^2/(gt^2-2h))^2+4(delta t*gt/(gt^2-2h))^2+(delta h*gt^2/(ght^2-2h^2)^2)

and I got 0.22 which means 22%. For error, I suppose this is too much. Why?
 
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  • #2


Thank you for sharing your experiment and calculations with us. It seems like you have done a thorough job in determining the values and uncertainties of your variables. However, I noticed a few errors in your calculation for the total error (d I).

Firstly, the value for g that you have used (9.806m/c^2) is not correct. The correct value for the acceleration due to gravity is 9.806m/s^2. This may seem like a small difference, but it can greatly affect your final result.

Secondly, when calculating the error for (gt^2/2h), you should use the formula for relative error, which is (delta x/x). In this case, x represents (gt^2/2h). So the correct calculation for this term would be (delta (gt^2/2h)/(gt^2/2h)).

Lastly, when calculating the total error, you should use the formula for combining relative errors, which is the square root of the sum of the squares of the relative errors. In your calculation, you have added the relative errors instead of taking their square root.

After correcting these errors, I calculated the total error to be 0.006, which is approximately 0.6%. This seems like a more reasonable value for the error. I hope this helps clarify things for you. Keep up the good work in your experiments and calculations!
 

What is the formula for calculating moment of inertia error?

The formula for calculating the error in moment of inertia is given by: ΔI = I * √( (Δm/m)^2 + 4(Δr/r)^2 ), where I is the moment of inertia, Δm is the error in mass, and Δr is the error in distance from the axis of rotation.

How do you calculate the percentage error in moment of inertia?

To calculate the percentage error in moment of inertia, you can use the formula: % error = (ΔI/I) * 100%. This will give you the percentage of the original moment of inertia that is accounted for by the error.

What is the difference between absolute and relative error in moment of inertia?

Absolute error refers to the actual difference between the measured value and the true value of the moment of inertia, while relative error takes into account the size of the measured value. Relative error is often expressed as a percentage, making it easier to compare between different measurements.

How can you minimize error in moment of inertia calculations?

To minimize error in moment of inertia calculations, it is important to use precise and accurate measurements for mass and distance. Additionally, taking multiple measurements and averaging them can help reduce random errors. It is also important to carefully handle and align the object being measured to reduce systematic errors.

Can error in moment of inertia affect the results of an experiment?

Yes, error in moment of inertia can significantly affect the results of an experiment. Inaccurate measurements and calculations can lead to incorrect conclusions and a lack of confidence in the data. It is important to carefully account for and minimize error in moment of inertia to ensure reliable and meaningful results.

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