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1. Homework Statement
The 70N force acts on the end of the pipe at B. determine the angles theta between 0 and 180 of the force that will produce maximum and minimum moments about point A.
2. Homework Equations
FBD is attached.
3. The Attempt at a Solution
I made the following equation then took its derivative and put it equal to 0. The problem here is that I only get one value of theta. the one which gives the maximum value of the moment. there isn't any other value of tan coming withing 0180. How do I get the minimum value of theta from this method. Wasn't I automatically supposed to get two value of theta from the first derivative and then I could I have gone further to second derivative to check if it was min or max. I am stuck.
Equation : [tex]M = (70cos\theta * 0.9) + (70sin\theta * 0.7)[/tex]
Derivative : [tex] = 63sin\theta + 49cos\theta [/tex]
The 70N force acts on the end of the pipe at B. determine the angles theta between 0 and 180 of the force that will produce maximum and minimum moments about point A.
2. Homework Equations
FBD is attached.
3. The Attempt at a Solution
I made the following equation then took its derivative and put it equal to 0. The problem here is that I only get one value of theta. the one which gives the maximum value of the moment. there isn't any other value of tan coming withing 0180. How do I get the minimum value of theta from this method. Wasn't I automatically supposed to get two value of theta from the first derivative and then I could I have gone further to second derivative to check if it was min or max. I am stuck.
Equation : [tex]M = (70cos\theta * 0.9) + (70sin\theta * 0.7)[/tex]
Derivative : [tex] = 63sin\theta + 49cos\theta [/tex]
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