As physics % error help urgent please Watch

Megan_90
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#1
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Hi,

I am stuck with these question, please help me before tomorrow.

1. for a cube of length (5.0+0.2)cm and mass (500+1)g calculate:
a) the percentage error in length
b)the percentage error in mass,
c)the percentage error in volume
d) density
e) the percentage error in density.

Please help this is very urgent!!
thanks,
Megan
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J_T_
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Percentage uncertainty=(absolute uncertainty/measured value)*100

Should be obvious for the a and b.

Volume=l*w*h.
When you're multiplying or dividing you have to add percentage uncertainties. Say the percentage uncertainty you calculated for length in a was x. Therefore the percentage uncertainty in the volume would be x+x+x.
Density=m/v
If the percentage uncertainty in the mass was y and the percentage uncertainty of the volume you calculated above was z then as you are dividing, same rule applies as before, you add the two percentage uncertainties together y+z.
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Megan_90
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(Original post by J_T_)
Percentage uncertainty=(absolute uncertainty/measured value)*100

Should be obvious for the a and b.

Volume=l*w*h.
When you're multiplying or dividing you have to add percentage uncertainties. Say the percentage uncertainty you calculated for length in a was x. Therefore the percentage uncertainty in the volume would be x+x+x.
Density=m/v
If the percentage uncertainty in the mass was y and the percentage uncertainty of the volume you calculated above was z then as you are dividing, same rule applies as before, you add the two percentage uncertainties together y+z.
is the percentage error the same as the percentage uncertainty?? coz the questions asks for percentage error.
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Megan_90
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also I can't figure out which one is absolute uncertainty.. I find it confusing :confused:
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Megan_90
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It's okay I managed to work it out. Thanks for the help anyway.
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J_T_
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(Original post by Megan_90)
is the percentage error the same as the percentage uncertainty?? coz the questions asks for percentage error.
Yeah same thing.
(Original post by Megan_90)
also I can't figure out which one is absolute uncertainty.. I find it confusing :confused:
It's the +/- thing after the measured value.
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