A pole BC is supported by the cable AB as is shown in the figure. If the magnitude of the force applied on the point B is 70 lb, and the moment of this force about the x-axis is -763 lb ft, determine the pole lenght.
I'LL ATTACH AN IMAGE SO YOU CAN SEE IT.
τ= torque or moment of force
τ= r X F
Tτ=(r1 + r2) x F
The Attempt at a Solution
I don't know how to compute the lenght, I was thinking about it maybe was related with the torque or moment of force (let me know if this is true).
What I tried to do was this:
r1= 4i + 6k
e=4/√52 + 6/√52
F= 70(4/√52 + 6/√52) = 38.82i+58.24k
and by performing the determinant
τ= -0.04 lb/ft
So far I should've got the T1 and now I'd do the same but this time with other vectors ⇒ 4i-6k
I don't think it's correct since I got a result on differents units that don't measure the lenght. PLEASE TRY TO TELL WHAT I'M WRONG AND WHAT I'M RIGHT.