The railway crossing gate consists of the 105-kg gate arm having a center of mass at Ga and the 260-kg counterweight having a center of mass at Gw. (Attached Figure)
Determine the magnitude and directional sense of the resultant moment produced by the weights about point B.

Question

The railway crossing gate consists of the 105-kg gate arm having a center of mass at Ga and the 260-kg counterweight having a center of mass at Gw. (Attached Figure)
Determine the magnitude and directional sense of the resultant moment produced by the weights about point B.

anonymous · Answer

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anonymous · Answer

I am able to determine M about B caused by Ga. ra = < -2.5 , 0.75 , 0 > and Ga = < 0 , -(105)(9.81) , 0 >

anonymous · Answer

ra x Ga = 2452.5 N*m

anonymous · Answer

However, I cannot get the position vector for Gw as I don't seem to see how to calculate the y coordinate. I don't see the vertical distance given in the problem. I have rw = <0.5, ? , 0 >

anonymous · Answer

Gw = < 0 , -(260)(9.81) , 0 >. Thanks for any pinpoint on this problem :)

anonymous · Answer

I think once I have the vector position of Gw. I would find its cross product , and just add Ma and Mw to get the total M.