If the roller at A and the pin at B can support a load upto 4kN and 8kN, repsectively, determine the maximum intensity of the distributed load w, measured in kN/m, so that failure of the supports does not occur.

Solution :

Taken moment about point B;

[tex]$\sum M_B = 0$[/tex]

[tex]$\left[(w)(4)(2)-N_A \sin 30^\circ (3)(\sin 30^\circ)-N_A \cos 30^\circ(3 \cos 30^\circ +4) \right] =0$[/tex]

[tex]$N_A = 1.2376w$[/tex]

[tex]$\sum F_x = 0$[/tex]

[tex]$N_A \sin 30^\circ - B_x = 0$[/tex]

[tex]$B_x = 1.2376w \times \sin 30^\circ$[/tex]

[tex]$B_x = 0.6188w$[/tex]

[tex]$\sum F_y = 0$[/tex]

[tex]$B_y+N_A \cos^\circ - (w \times 4) = 0$[/tex]

[tex]$B_y+(1.2376w) \cos 30^\circ - (w \times 4)=0 $[/tex]

[tex]$B_y = 2.9282w$[/tex]

Now calculating the resultant force at B,

[tex]$F_B= \sqrt{B_x^2+B_y^2}$[/tex]

[tex]$F_B= \sqrt{(0.6188w)^2+(2.9282w)^2}$[/tex]

     = 2.9929w

For no failure,

[tex]$N_A<4 \ kN $[/tex]

2.9929 w < 4 kN

[tex]$w < 3.232 \ kN/m$[/tex]

And,

[tex]$F_B < 8 \ kN$[/tex]

2.9929 w < 8 kN

w < 2.673 kN/m

For the safe operation, w = 2.673 kN/m  

A _________ is interesting only if the statistics computed from transactions covered by the rule are different than those computed from transactions not covered by the rule.

Technician A says that a way to prevent galvanic corrosion is to duplicate the original installation method. Technician B says that a way to prevent galvanic corrosion is to reuse coated bolts. Who is right