What is the reaction of a hinged beam with a mass and light cable?

[farheld]

1. A Beam of negligible weight AB, carrying a mass of 70kg at its end B, is hinged to a vertical wall at A and held at B 30degrees to the vertical wall by a light cable BC of 5mm diameter, C is at a distance vertically above A

Find the reaction of the beam at the wall and predict the behaviour of the cable by determining its Young;s Modulus if it is not allowed to extend more than 0.1% of its length under any condition




2. Stuck on what equations i need to use for the above



3. I drew the diagram in question and that's as far as i got =/

http://img201.imageshack.us/img201/1646/problemib2.jpg

 

[FredGarvin]

Did you try to sum the moments about A?

 

[farheld]

Did you try to sum the moments about A?

Sorry, i don't have any idea what you're talking about =/

 

[Pyrrhus]

Fred is talking about taking moment or torque about A, the second condition of static equilibrium.

I would imagine you have to find the force along the cable and then use Hooke's Law in order to calculate the Young's Modulus or Modulus of elasticity.

 

[farheld]

I still havn't been able to get my head round it.

Thing is, i havn't been taught how to do it, therefore i don't understand the terms you are using.

I need maybe a worked example of something similar that i can understand the formula to use and the method of working it out.

Thanks,

Joel

 

[haynewp]

Go through the statics tutorials.

http://web.umr.edu/~bestmech/