# Need Some help with torque

1. Oct 10, 2004

### thennigar

first post.... see how it goes.

I need some help with a step ladder question. Wont bother giving the question i just need help on how to go about it.

Stepladder of negligible weight, person standing at a point on the ladder. Need to know how to go about finding tension on a crossbar. all the dimensions are givin. And the surface is frictionless.

Thanks

2. Oct 10, 2004

### Clausius2

You should clarify a bit more the geometrics. How are you modelling the person weight?. Is it a puntual force over the crossbar?. How the stepladder is supported?

3. Oct 10, 2004

### rcgldr

To determine tension on the cross bar you need to know how much it flexes. If the cross bar isn't mounted by bearings to the ladder as is done so often to simplify the study of statics, it's gets really complicated. You'd need to know how the cross bar is mounted, and how much the connection area flexes.

4. Oct 10, 2004

### rcgldr

If the cross bar has a frictionless connection to the ladder there's no tension at all (as there's nothing to provide a tensioning force at the connections). For example, hang a weight on a broom stick with the broom stick resting on two frictionless supports. There's no net tension because the broom stick simply flexes, creating internal tensions and compressions.