Why is there a negative in Hooke's Law (F = -kx)

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SUMMARY

Hooke's Law is defined by the equation F = -kx, where F represents the force exerted by the spring, k is the spring constant, and x is the displacement from the equilibrium position. The negative sign indicates that the force exerted by the spring is always in the opposite direction of the displacement. This relationship illustrates that when a force is applied to compress or extend the spring, the spring reacts with an equal and opposite force, adhering to Newton's third law of motion. Understanding this principle is crucial for analyzing spring dynamics in physics.

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For Hooke's Law, why is there a negative in F = -k*x? Is it because k is the reaction force against the force applied on the spring and not the force pushing or pulling on it? For example, let's say that the origin is set where the spring ends when it's in equilibrium with no forces applied to it. However, when I push on to it, that force is going left into the negative direction, but the reaction force to that is pointing the positive direction (right). Therefore, is the reason why there's a negative in the Hooke's Law equation is to calculate for the reaction force while giving it less thought on where is the action force is going?
 
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That's right. The force of the spring on whatever is pulling/pushing it is always directed opposite to the displacement.
 
Drakkith said:
That's right. The force of the spring on whatever is pulling/pushing it is always directed opposite to the displacement.
Thank you very much for your speedy reply.
 

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