Calculating the 'Kicking Out' Force in Toppling Objects

[derryck1234]

Hi. I am trying to calculate the 'kicking out' force created when an object topples over. Attached is a picture of what I mean. The body in the picture topples in a clockwise direction as shown, with its initial pivot point at 'a'. The centre of gravity of the body is shown as cg.

Now I have been told that there is a force that causes the rod to kick back from this pivot position due to the centre of gravity that 'wants' to fall straight down. How would I work this out?

 

[SteamKing]

These are the kinds of problems which are analyzed by applying Newton's Laws of motion to the toppling structure; i.e., that's why you took a dynamics class in college.

As with any problem involving statics or dynamics, start with a free-body diagram and determine what forces and moments are acting on the structure when it is at an arbitrary angle. It's not clear from you diagram how the process of toppling gets started.

 

[derryck1234]

Answer so far

Hi. The body is started by applying a horizontal force at the top until the body's centre of gravity causes it to topple, from this point gravity takes over.

My colleague in the office worked on it and made a spreadsheet. We would just like to confirm whether our thinking is correct. The spreadsheet is attached. It uses the energy approach in the first tab and the equations of motion in the second.

Regards

DerryckView attachment Falling Tower Forces.xlsx