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Determine the moment of each of the three forces about point B. Please see attached figure.
 one year ago
 one year ago
Determine the moment of each of the three forces about point B. Please see attached figure.
 one year ago
 one year ago

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redpandaBest ResponseYou've already chosen the best response.0
I know how to find it about point A, but I am having difficulty seeing how to find it for point B.
 one year ago

Yahoo!Best ResponseYou've already chosen the best response.0
Seperately Solve the hinge forces...:)
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
I don't understand what you mean.
 one year ago

azolotorBest ResponseYou've already chosen the best response.0
He means, solve for the force at each of the points where there is an angle and then sum them to see where the net force is
 one year ago

JamesJBest ResponseYou've already chosen the best response.1
You guys have missed the question. What is being asked is what the moment due to each force. Can you help the questioner?
 one year ago

JamesJBest ResponseYou've already chosen the best response.1
I'll do it then. What is the definition of the moment of a force?
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
The moment of a force is its ability to create rotation.
 one year ago

JamesJBest ResponseYou've already chosen the best response.1
Yes, but mathematically and precisely, with a formula?
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
M = F*d, where d is the distance between the point of application and the pivot
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
(btw thanks for your help, I have been lost for hours)
 one year ago

JamesJBest ResponseYou've already chosen the best response.1
Yes. Now, let's start with F3. What's the moment due to that force?
 one year ago

JamesJBest ResponseYou've already chosen the best response.1
..the moment of F3 about B? Well, what's the distance of the application of the force from B? Zero. Can F3 make something rotate *around* B? No. Therefore the moment due to F3 is zero.
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
ah!! that's what I thought! but I thought it would be wrong bcs it was 0
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
bcs the position vector at B is <0,0,0> and crossing it with the F3 vector would give zero.
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
But one question, would not the perpendicular component of F3 try to produce some moiton that vertical bar?
 one year ago

JamesJBest ResponseYou've already chosen the best response.1
The question at a qualitative level is this: can a force applied at a point cause other things to rotate about that point? And the answer is no. It might make that point and the solid attached to it move, but it doesn't cause rotation around that point per se. Hence: A force applied to a point causes no rotation about that point.
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
its the same as if I go to the center of the bolt and try to make it rotate applying a force right on the center of rotations. no rotation would happen!
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
I have to move at least an infinitesimally small amount away from that center of rotation for it to actually rotate (no matter how large the force). Motion may occur in the form of displacement, but no actual rotation about that point :D
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
for f2. I think it goes like this:
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
the position vector would be : <3, 4 , 0>
 one year ago

JamesJBest ResponseYou've already chosen the best response.1
No, you want the positive vector RELATIVE TO B
 one year ago

JamesJBest ResponseYou've already chosen the best response.1
Which will be just r = <0,4,0>
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
hmmm would not that be moving to the right of B and up from B?
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
oh yes! sorry I was doing F1 mistakenly !
 one year ago

JamesJBest ResponseYou've already chosen the best response.1
oh right. yes, F2. Doing them backwards because F1 is the most complicated.
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
r = <0, 4 0 > ; F2 = < 300*sin(60) , 300 *cos(60) , 0 >
 one year ago

JamesJBest ResponseYou've already chosen the best response.1
check your sin and cos there
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
ah, i see that I did. I was putting it on the wrong side
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
< 300*cos(60) , 300 *sin(60) , 0 >
 one year ago

JamesJBest ResponseYou've already chosen the best response.1
Yes. Ok, you've got it. I'll leave you with F1 now by yourself.
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
I have dyslexia and its hard to see things sometimes! Thanks for your patience
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
for F1, r = < 3 , 4 , 0 >
 one year ago

redpandaBest ResponseYou've already chosen the best response.0
F1 = < 250*sin(30) , 250*cos(3), 0 >
 one year ago

JamesJBest ResponseYou've already chosen the best response.1
Looks right (30 obviously). Now calculate the cross products
 one year ago
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