Calculate Static Equilibrium: SOH/CAH/TOA?

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SUMMARY

Calculating static equilibrium requires understanding the relationship between angles and their respective components. When using the SOH-CAH-TOA mnemonic, the sine function is applied to the component opposite the angle, while the cosine function is used for the adjacent component. This relationship is contingent upon whether the angle is measured from the x-axis or y-axis. If the angle is relative to the y-axis, the sine function applies to the x-component, necessitating careful attention to the reference axis when resolving forces.

PREREQUISITES
  • Understanding of trigonometric functions: sine, cosine, tangent
  • Familiarity with static equilibrium concepts in physics
  • Ability to resolve vectors into components
  • Knowledge of angle measurement relative to axes
NEXT STEPS
  • Study vector resolution techniques in physics
  • Explore advanced applications of SOH-CAH-TOA in static equilibrium problems
  • Learn about the implications of angles not aligned with standard axes
  • Practice problems involving static equilibrium with varying angle references
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Students in physics, engineering professionals, and anyone studying mechanics who needs to master the calculation of static equilibrium and vector components.

Mason98
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Homework Statement
Sin for Y axis and Cos for X axis?
Relevant Equations
Sin = opp/hyp Cos = Adj / hyp
When calculating static equilibrium, i know that you have to split for example, F1 into F1x and F1y. when using soh/cah/toa is it always SIN for the Y axis and always Cos for the X axis? I've been following this method and getting it wrong some times it's really stressing me out, Thanks for any help in advance.
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Mason98 said:
when using soh/cah/toa is it always SIN for the Y axis and always Cos for the X axis?
No. It all depends on what angle you are using. If the angle is with respect to the x-axis, then fine: The x-component would use cosine, etc. But if the given angle is with respect to the y-axis, things are reversed.

Remember that sinθ = cos (90° - θ).
 
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so that is how in the picture Fax is sin because the angle given is in respect to the y-axis which would mean to use sin?
 
Mason98 said:
so that is how in the picture Fax is sin because the angle given is in respect to the y-axis which would mean to use sin?
Exactly!
 
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Doc Al said:
Exactly!
Thank you very much! I appreciate your help :)
 
But if you adopt this as a new rule-of-thumb, you'll still be in a pickle when the problem gives you an angle which is relative to neither the x nor y axis.
 

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