4.1 THE BASIC EQUATIONS OF STATICS

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There are two basic balances that must exist in any statics problems.

if the sum of the forces is not zero, then the system will undergo translation, and the problem cannot be solved with statics methods.

if the sum of moments is not zero, then the system will undergo rotation, and the problem cannot be solved with statics methods.

At least one of these two equations will appear in every statics problem.

A simple example,

Let's consider a force balance problem, ([Hibbeler, 1992]prob 3-40, pg. )

4.1.1 Practice Problems

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1. Two cables (AB and AC) and a force (P) act on the top of a flag pole (AD). Find the magnitude of force P required to keep the flag pole standing? Assume that cable AB is under 5 KN of tension.

ANS

4.1.2 References

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Hibbeler, R.C., Engineering Mechanics: Statics and Dynamics, 6th edition, MacMillan Publishing Co., New York, USA, 1992.