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shade585
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Homework Statement
the mass of a particular sample of rock retrived from Mars is m=772.2+or-0.2g. The sample is in the shape of cylinder of height h=10+or-0.1 cm and base radius r=2.5 +or-0.1cm. calculate the density of the rock sample in units of kg/m^3. You must state your result in the correct units with its associated uncertainty. The volume of a cylinder is V=pir^2h.
Homework Equations
p=m/v
The Attempt at a Solution
I can get the density but I cannot get the correct uncertainty.
The density I get is
(772.2g/196.35cm^3)((1 kg/m^3)/10^-3g/cm^3)=3932.77 kg/m^3
I believe the uncertainty is supposed to be +or-400 but I end up with four.
(delta p)/(3.9g/cm^3) = .2/772.2 + .14/196.35
delta p = .004 g/cm^3
.004 g/cm^3 ((1kg/m^3)/(10^-3 g/cm^3) = 4 kg/m^3
Im new to this propagation of errors stuff. Using sig figs other people in my class got either 4000 +or- 400(or +or- 100) I can't remember.