The moment of inertia of a flywheel disc is found from

PHYSICS · Multi-part · Fermi University Physics · Scientific Practice & Experimental Methods · Uncertainty in measurement · Uncertainty in measurement

Measurement and Method, Ch Propagating uncertainty into the quantity you actually want

Problem

I = \tfrac12 M R^2

, with mass

M = (2.400 \pm 0.006)\,\mathrm{kg}

and radius

R = (0.1500 \pm 0.0015)\,\mathrm{m}

, each uncertainty a standard deviation and

M

and

R

measured independently on different instruments. ((a)) Compute

I

. ((b)) Lay out a propagation table giving the relative contribution of

M

and of

R

I

, using the shortcut rules, and combine them to give

u(I)

and

I = \bar I \pm u(I)

. ((c)) Identify which input dominates the total uncertainty, and state the new total relative uncertainty if that input's uncertainty were halved, the other left unchanged.

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