Unsure of mechanics problem, circular door on hinge...

[aaroon]

1. In the attached imjage, the centre of gravity of an open door acts at G equal to 255N;
a) Determine the x,y,z, components of reaction at the hinge A in equilibrium
b) Determine the force along CB

Little stuck with this problem, obviously this falls under resolving forces. I assumed Az,Ay = 0 as gravity is acting straight down and Az= 255N - (verical component of reaction given by CB). Any help would be appreciated :)

[PLAIN]http://www.imgur.com/V9G2Kz7[/CENTER]​

 

[BvU]

Hello Aaroon, welcome to PF !

As much as I'd like to help you, I can't make heads or tails out of this post (well, see below...). Would you be so good as to sort out things using the template that accidentally got deleted (it is compulsory in PF, we in fact aren't allowed to assist if it's missing...) ?

Homework Statement

Homework Equations

The Attempt at a Solution

[/B]
It seems they want the components of the force on A and along CB.

The lot is in equilibrium, so you should be able to set up a force balance plus a torque balance. The Ax , Ay and Az you provide don't give a balance in either of these two...

 

[Baluncore]

Is the line CB a strut that supports the door in the open position, ie door horizontal ?
Does the strut CB bear on a point on the circumference of the door, an angle theta from the y-axis ?

 

[aaroon]

Is the line CB a strut that supports the door in the open position, ie door horizontal ?

Hi Baluncore, thanks for your reply, my understanding is CB supports the door in the open position as you say.

Does the strut CB bear on a point on the circumference of the door, an angle theta from the y-axis ?

That is also my question, I would assume so otherwise the angle has no purpose.

 

[haruspex]

I assumed Az,Ay = 0 as gravity is acting straight down and Az= 255N

Meaning the components of the reaction at the hinge? No, all three will be nonzero.
Are you expected to work in terms of resolved components or vectors (including vector products)? I suggest the second would be neater.

 

[aaroon]

Are you expected to work in terms of resolved components or vectors (including vector products)? I suggest the second would be neater.

I believe resolved components but haven't been told explicitly.

 

[haruspex]

I believe resolved components but haven't been told explicitly.

Have you worked with vector products?

 

[Baluncore]

That is also my question, I would assume so otherwise the angle has no purpose.

The lack of a radius symbol suggests the strut contacts the circumference at the radius of 0.9m in direction theta.
I think the question has now been resolved, so I'll leave you to find the answers.