How Should a Plank Be Supported for Balance with Unequal Weights at Its Ends?

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SUMMARY

The discussion centers on determining the optimal support point for a 5m plank used as a see-saw by two children weighing 25kg and 20kg, translating to forces of 245N and 196N, respectively. The key concept is balancing the torques created by these weights around the pivot point. The solution involves ensuring that the net torque equals zero, which can be achieved by calculating the distances from the pivot to each child's position. The participants emphasize that understanding torque is crucial for solving the problem effectively.

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  • Familiarity with equilibrium concepts in physics
  • Ability to apply the principle of moments
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alexo
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Homework Statement


I think I'm being a bit dull today but I seem to be having real trouble understanding this question...

Two children wish to make a see-saw from a 5m plank of wood, the children weigh 25kg and 20kg. They wish to sit right on the ends of the plank. Where should the plank be supported in order for it to balance...

Homework Equations


t=RF

The Attempt at a Solution


I know that Net ACWM should = CWM...
I found the weight in Newtons of the kids...196N and 245N..
I added the two forces together to get the opposing force of the pivot, 441N

But now I'm stuck... and have no idea where to take it from here :(

Thanks :) Alexo.
 
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I don't think the question is dealing with the pivot (in many of these problems the means of rotation, like the pulley is deemed massless and frictionless.)
the question is about torque, so ask yourself, how can the plank be placed so there is no torque? the only equation you need you already have.
 

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