Friday 20 May 2011

Asta e fune

One end of a uniform beam weighing 30N and 1 m long is attached to a wall with a hinge. The other end is supported by a wire. Find the tension of the rope. What is the action on the wall?


A+T+W=0  (somma vettoriale)

r×W+2r×T=0 (polo in O)

Momento del peso = L m g sin 60°/2

Momento tensione fune = LT sin 30°

  L m g sqrt(3) / 4 = L T /2

   T = 2mg/sqrt(3)

A_x= T cos 60° = mg  ;  A_y= mg-T sin60°=mg-mg/sqrt(3)