Torque is same all along lever?

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SUMMARY

The discussion centers on the concept of torque in relation to lever arms and force. Torque is defined as the product of the perpendicular force and the distance from the pivot point (Torque = F * d). It is established that while the force required increases as the lever arm shortens, the torque must remain equal at the pivot point to maintain equilibrium. This understanding clarifies that torque is not the same as force, but rather a measure of rotational effect around a pivot.

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  • Understanding of basic physics concepts, particularly force and torque.
  • Familiarity with lever mechanics and pivot points.
  • Knowledge of mathematical relationships involving force and distance.
  • Conceptual grasp of equilibrium in physical systems.
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This discussion is beneficial for physics students, mechanical engineers, and anyone interested in understanding the principles of torque and lever mechanics in both theoretical and practical contexts.

yosimba2000
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Here's my background so you know where I'm having trouble. I've attached a picture.

I have to find the force produced by the muscle to keep the arm and ball at its current position in the picture. Now, I originally assumed Torque was Force in rotation, and intuitively thought you would need to use more force if you're closer to the pivot (shorter lever arm) than compared to the end (longer lever arm). I was right about force needed being greater as the lever arm got shorter, but I'm having touble understanding why the Torque along the lever must be the same. So, now I know Torque and Force are not the same.
Mathematically, I know there's only one right answer, but how about conceptually? What is torque if it's not force? What does it represent? Why isn't the torque increasing as the lever arm length decreases?

Thanks!
 

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Torque is the perpendicular force times the distance to the pivot point. It is completely different from force. it is F*d.
Given that, you can see that as d decreases, so does the torque.

In this case, in order to hold the weight steady, the two torques must be equal. Because d for the muscle is much less than the other, it requires a much larger force.

does that help?
 
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sorry, it still hasn't clicked. I mean, mathematically I agree with what you've said, but I still can't understand what Torque represents. What is it that makes it the same everywhere along the lever?
 
it is not the same everywhere along the lever. torque is only defined about a pivot point. For the arm to hold the weight steady, the two torques about that point must be equal.

I am at a loss for offering an easy conceptual understanding. I just think of it as F*d.
 
wait I think I've got it now. I was originally thinking of the upward force that the forearm would provide to support the ball, but now I'm thinking of the ball dragging down the forearm. And to balance that we need an upward force and the torques have to equal. Thanks a bunch!
 
you're welcome :)
 

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