- #1

Northbysouth

- 249

- 2

## Homework Statement

The turnbuckle is tightened until the tension in cable AB is 1.5 kN. Calculate the magnitude of the moment about point O of the force acting on point A.

## Homework Equations

ƩM

_{O}= sqrt(M

_{x}

^{2}+ M

_{y}

^{2}+ M

^{2})

## The Attempt at a Solution

First I identified the coordinates of points A and B:

A = (1.6, 0, 2.4)

B = (2.3, 1.4, 0)

OA = r = <1.6, 1.4, 0>

AB = <0.7, 1.4, -2.4>

|AB| = 2.865

λ

_{AB}= AB/|AB|

λ

_{AB}= 0,2443i + 0.4877j - 0.8377k

Then I took the dot product with the tension in the cable AB and the unit vector of AB

T

_{AB}.λ

_{AB}= 0.36645i + 0.73305J - 1.25655K

ƩM

_{O}= rXT

_{AB}

(0-1.75932)i -(-2.81796)J + (1.17288)k

ƩM

_{O}= 3.523

But it says my answer is wrong and I don't know where I'm going wrong.

Suggestions would be appreciated