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# Uncertainty watch

1. Okay, so I'm currently doing an investigation on determining the Young Modulus of a metal and for the evaluation it says that I need to detail the percentage uncertaintity for F - which is aquired from the F = W = mg, meaning that I need to take the mass into account.

The problem, however, is the slotted mass that we used during the experiment had no error value? It was just 0.10 - 1.00 kg without any errors. Nor is it stated anywhere? So does anyone know an estimation or anything I can do to find out the uncertainty?
2. (Original post by TarotOfMagic)
Okay, so I'm currently doing an investigation on determining the Young Modulus of a metal and for the evaluation it says that I need to detail the percentage uncertaintity for F - which is aquired from the F = W = mg, meaning that I need to take the mass into account.

The problem, however, is the slotted mass that we used during the experiment had no error value? It was just 0.10 - 1.00 kg without any errors. Nor is it stated anywhere? So does anyone know an estimation or anything I can do to find out the uncertainty?
The masses normally say 100g on, so you can assume that the masses are correct to 3sf each, so each one would be 100 ± 1 g. So each mass would have an estimated uncertainty of 1%. You would have to know information about the scales used to weigh them to find a more accurate error. i hope this helps!
3. (Original post by P_Digby)
The masses normally say 100g on, so you can assume that the masses are correct to 3sf each, so each one would be 100 ± 1 g. So each mass would have an estimated uncertainty of 1%. You would have to know information about the scales used to weigh them to find a more accurate error. i hope this helps!
Thanks I have another problem. I am told that I need to find the percentage uncertainty of the area - which is measured in m^2. However, the diameter of a wire is 0.24 ± 0.005 mm. If I were to convert it to m, what would happen to the ± 0.005?
4. 0.240 +- 0.005mm = (0.240 +- 0.005) *10^-3 m
r = (0.120 +- 0.0025)*10^-3 m
area = (4.5 +- 0.1)*10^-9 m^2

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