Calculating Tension in a Horizontal Bar Connecting Two Halves of a Ladder

[Fabio010]

Mass of man is = 80KG
Mass of the ladder is = 20 KG

Mass of the bar connecting the two halves of the ladder is negligible.

The friction force between floor and ladders are negligible. (floor is frictionless)

Question: find the tension in the horizontal bar connecting
the two halves of the ladder...


Here is the figure:

I am wondering if it is possible to calculate the tension, without knowing the dimensions of the ladder??It is not right?

 

[ehild]

The figure is very impressive!

I am wondering if it is possible to calculate the tension, without knowing the dimensions of the ladder??It is not right?

It is possible. Write up the equation for the momenta.


ehild

 

[Fabio010]

Equations for momenta, i think you mean torque right?.

 

[ehild]

Equations for momenta, i think you mean torque right?.

Yes, of course, sorry. I talked about torque in my language just before writing this letter and mixed.

Measure lengths in the unit shown in the figure when writing up the torques. But you need the angle between the legs of the ladder. It must be given. ehild

 

[Fabio010]

First of all i need to do a diagram of forces.

Is that right?

Ok so without the angle is is impossible to do the exercise?

 

[ehild]

It looks all right if the distances are correct.
ehild

 

[ehild]

Hi Fabio,

Can you proceed?
Write up the equations for the y components of forces for both legs, and also the torques. For those, you need the angle. Adding up the equations for the force components, you get N1+N2. Subtracting the equations for the torques, you get N1-N2. Determine them and use in the torque equation for one leg.


I go to sleep:zzz:

ehild

 

[Fabio010]

I talked to my teacher and he said that the exercise should have the dimensions.
And with the dimensions i could calculate the angle and do the exercise.

I have it done. Thanks for your help :)