Static Equilibrium - trick question?

AI Thread Summary
The discussion revolves around a physics problem involving a man standing on a board supported by two cables with different tensions. The initial assumption is that the man's weight is simply the sum of the cable tensions, leading to a weight of 500N. However, confusion arises regarding the use of torque and the position of the man on the board. Participants clarify that since no angles are provided, the cables can be assumed vertical, simplifying the problem. The overall sentiment is that the question is designed to mislead by following more complex problems with a straightforward solution.
prettydumbguy
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Homework Statement



A man stands on a board of negligible mass with a length of 10m is supported by 2 cables, one on the left on one on the right, with a tension of 300N and 200N respectively. How much does the man weigh in Newtons?

Homework Equations


F=ma
Torque= F*lever arm

The Attempt at a Solution


I'm tempted to just 500, but that's far to simple. I thought of setting up a torque equation, but I don't know how I would when I don't know his mass or where he stands. So, if I assume he's standing x meters from the left: 300(x)-200(10-x) + man(mans location) = 0.
So I set one of the cables as the axis of rotation: the left cable, giving me man(x)=200(10).
Multiply out to get man(x) = 2000.
Now I have two variables I can't get rid of.

But I still really want to just sum all the forces along the y-axis and set it equal to zero: 300 + 200 -man = 0, so I still get 500.
Am I just overthinking the hell out of this?
 
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Assuming the cables are vertical, yes, you're overthinking it. It is as easy as it seems.
 
haruspex said:
Assuming the cables are vertical, yes, you're overthinking it. It is as easy as it seems.
No angles were given, so I assume that they are vertical. The question comes after two much more in depth SE problems, hence my confusion. Thanks!
 
prettydumbguy said:
No angles were given, so I assume that they are vertical. The question comes after two much more in depth SE problems, hence my confusion. Thanks!
Sounds like a classic way to catch people out, follow some tough questions by an easy one with redundant information.
There's an old geometry problem where you ask someone to cut an L shape, consisting of three squares, into four identical pieces. When they've solved it, you say ok, try this harder one: cut a square into five identical pieces.
 
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