# Homework Help: Hollow square size

1. Nov 26, 2015

### sekedarimaji

1. The problem statement, all variables and given/known data
I'am trying to make a simple machine which is to lift a display up and down. The construction mostly using hollow square.
so far I got the weight of the display and the support is 25 Kg and I have this kind of construction.

if simplified become like this

2. Relevant equations
which is the right moment happen in that construction?
a.

b.

Is that necessary to calculate the moment?
how do i get the right hollow square size?

3. The attempt at a solution

2. Nov 26, 2015

### Staff: Mentor

Assuming your frame is rigid, both diagrams are equivalent.

3. Nov 27, 2015

### sekedarimaji

so calculating the moment is not necessary?
is there any formula to get the right size of hollow square?

4. Nov 28, 2015

### Staff: Mentor

Which moment, necessary for what?
Right size for what?

5. Nov 28, 2015

### CWatters

Ask yourself what forces each tube is subject to. Perhaps start with the horizontal tube.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted