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renaldocoetz
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Net torque and net force in equilibrium.. Help please
The diagram shows a uniform plank of length 5.0m and weight 225N that rests horizontally on 2 supports, with 1,1 m of the plank hanging over the right support.
http://www.postyourimage.com/view_image.php?img_id=Oc9PYdcDMUhBrGB1196709689 [Broken]
To what distance x can a person who weighs 450N walk on the overhanging part of the plank before it just begins to tip?
Net force on Y-axis = 0
Net torque on right support = 0
Net torque on left support = 0
I used these 3 formulas to end up with 3 unknowns in order to work out x but ended up with 0x = 234 :(
Net torque right post = -FNl(3,9) + Wp(1,4) - Wmx = 0
Net torque left post = -Wp(2,5) + FNr(3,9) - Wm(3,9 + x)
FNr + FNl -225 -450 = 0
i used counter-clockwise rotation as positive
I combined these 3 formulas in an attempt to get x but it didnt work quite so well. Is this a wrong approach or might my mistake just be in my algebra?
Please help any1
thxPS
FNl = normal force of left support on plank upwards
FNr = normal force of right support on plank upwards
Wp = weight of plank
Wm = weight of man
Homework Statement
The diagram shows a uniform plank of length 5.0m and weight 225N that rests horizontally on 2 supports, with 1,1 m of the plank hanging over the right support.
http://www.postyourimage.com/view_image.php?img_id=Oc9PYdcDMUhBrGB1196709689 [Broken]
To what distance x can a person who weighs 450N walk on the overhanging part of the plank before it just begins to tip?
Homework Equations
Net force on Y-axis = 0
Net torque on right support = 0
Net torque on left support = 0
The Attempt at a Solution
I used these 3 formulas to end up with 3 unknowns in order to work out x but ended up with 0x = 234 :(
Net torque right post = -FNl(3,9) + Wp(1,4) - Wmx = 0
Net torque left post = -Wp(2,5) + FNr(3,9) - Wm(3,9 + x)
FNr + FNl -225 -450 = 0
i used counter-clockwise rotation as positive
I combined these 3 formulas in an attempt to get x but it didnt work quite so well. Is this a wrong approach or might my mistake just be in my algebra?
Please help any1
thxPS
FNl = normal force of left support on plank upwards
FNr = normal force of right support on plank upwards
Wp = weight of plank
Wm = weight of man
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