The tower crane is used to hoist a 2.0mg- load upward at constant velocity. The 1.7Mg- jib BD and 0.6-Mg jib BC have centers of mass at G1 and G2, respectively. Determine the required mass of the counterweight C so that the resultant moment produced by the load and the weight of the tower crane jibs about point A is zero. The center of mass for the counterweight is located at G3.

Question

The tower crane is used to hoist a 2.0mg- load upward at constant velocity. The 1.7Mg- jib BD  and 0.6-Mg jib BC  have centers of mass at G1   and G2, respectively. Determine the required mass of the counterweight C  so that the resultant moment produced by the load and the weight of the tower crane jibs about point A is zero. The center of mass for the counterweight is located at G3.

anonymous · Answer

attachment

anonymous · Answer

I have no idea. Please don't just give me an answer, I would love to see the steps.

anonymous · Answer

? any ideas.

anonymous · Answer

this from statics?

anonymous · Answer

yes

anonymous · Answer

just start drawing vectors I guess :P   sum of torques =0

anonymous · Answer

but from where? lol. AB AG1 AG3 AG2 AD ?

anonymous · Answer

i'll dl the jpeg and edit it,  easier than trying to draw everything in this sketch tool

anonymous · Answer

ok

anonymous · Answer

i understand position vectors, but from there????

anonymous · Answer

attachment

anonymous · Answer

I think it's just sum of torques...  usually it's sum of torques and sum of forces but for this problem I can't see why you'd need sum of forces...

anonymous · Answer

angles and magnitudes of r's are all defined

anonymous · Answer

eg.:  the black r is sqrt(23^2 +12.5^2)   and the angle between F and r is arctan(12.5/23)

anonymous · Answer

does that help at all or was it pretty much stuff you knew already...

anonymous · Answer

no that really did help, thanks.