The overturning moment of an object is the moment of energy capable of upsetting the object; that is, the point where it has been subjected to enough disturbance that it ceases to be stable, it overturns, capsizes, collapses, topples or otherwise incurs an unwanted change in its circumstances, possibly resulting in damage and certainly resulting in inconvenience.
Weigh the test item and the test fixture to which it is mounted. The weight can be recorded in either conventional or metric measure.
Determine the center of gravity of the test item. Measure the distance from the bottom of the item to the center of gravity with the tape measure.
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Calculate the root mean square acceleration of the test item.
Multiply the Grms by the height of the center of gravity. Multiply the result by the weight of the test item and the test fixture to which it is mounted. The result is the overturning moment (G x CG x 1W = OM)
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A calculator that can accept raw data to calculate the root-mean-square is preferred for this work and simplifies the calculations immensely.