Reduction of resultant Moment/Force

[Saladsamurai]

[SOLVED] Reduction of resultant Moment/Force

So I have calculated the resultant force correctly but my solution for distance is incorrect. I keep getting 6.08 ft but the correct solution is 6.57 feet from B.

I found [itex]F_r=798.499[/itex] which is correct. Then I used,

[tex]\sum M_B=\frac{3}{5}(500)(9)+6(1200)+\frac{12}{13}(260)(4)=4860 lb\cdot ft[/tex]

Then [itex]d=\frac{M_r}{F_r}=6.09 ft[/itex] Where is my error?

 

[Dick]

F_r is the total magnitude of the resulting force, yes. But in the formula d=M/F (where M is the torque, and d is distance from axis), you want the F to be component of the total force that exerts torque. That would be the vertical component only of the total force.

 

[ogb p]

It seems like you have made a mistake in your calculation for the distance. Double check your formula and make sure you are using the correct values for the moment and force. It's possible that you may have mixed up the units or made a calculation error. Also, make sure you are using the correct sign convention for the moments. It's always a good idea to double check your work to catch any errors.