- #1

papasmurf

- 22

- 0

## Homework Statement

Determine the tension in cables BC and BD, and reactions at the ball-and-

socket joint at A for the mast shown in the figure.

Answers are given by the teacher for checking purposes: TC=707 N; TD=1500 N, Ax=0 N,

AY=0 N, AZ=1500 N

## Homework Equations

ƩM

_{x}=0

ƩM

_{y}=0

ƩM

_{z}=0

ƩF

_{x}=0

ƩF

_{y}=0

ƩF

_{z}=0

## The Attempt at a Solution

Taking clockwise to be the positive moment direction about the x-axis. In other words, if you are standing at the positive side of the x-axis and look down towards the negative side, the moment will be spinning clockwise.

ƩM

_{x}=0= -1kN(6m) + T

_{BD}cos(tan

^{-1}(3/6))cos(45)[kN]*(6m)

...this attempt at a solution is way wrong.

The way I thought about it was, take the cos(tan

^{-1}(3/6)) to get your T

_{BD}in the yz-plane. Next, I took the cos(45) to get it going strictly in the y direction, and then multiplied by the perpendicular distance from the x-axis, 6 m. The problem I'm having is knowing what to do with the given force of 1 kN. There is no specified direction or any information stating where this force is going to. I know how to use the moment and force equations if I can get these things broken up into components correctly.