Engineering Mechanics - Equilibrium of a Particle - Discussion
Discussion Forum : Equilibrium of a Particle - General Questions (Q.No. 6)
6.

Determine the force F needed to hold the 4-kg lamp in the position shown.
Discussion:
6 comments Page 1 of 1.
Thirupathaih said:
1 decade ago
Free body diagram at B we assume Tension at A is x tension at C is y
according to equilibrium force system
x cos60+y cos30=0 then x=-1.732y -----(i)
and
x sin 60 - ysin30-39.2=0----(2)
from equation 1 & 2
-1.732y sin60-y sin30=39.2=> -2.22y=39.2
y=17.81N
and tension acting at D is z according to the fig z=y
2ysin30-f=0=> f=17.822N
according to equilibrium force system
x cos60+y cos30=0 then x=-1.732y -----(i)
and
x sin 60 - ysin30-39.2=0----(2)
from equation 1 & 2
-1.732y sin60-y sin30=39.2=> -2.22y=39.2
y=17.81N
and tension acting at D is z according to the fig z=y
2ysin30-f=0=> f=17.822N
Mu" said:
1 decade ago
I think there maybe you have do something wrong in first equation with the sign.
*-x cos 60+y cos 30= 1.732
You have do great work.
Thank for your solution.
*-x cos 60+y cos 30= 1.732
You have do great work.
Thank for your solution.
Sowndar said:
1 decade ago
Particles are in equilibrium.
So, lamp = 4 kg.
= 4 x 9.81.
= 39.24 N.
So, lamp = 4 kg.
= 4 x 9.81.
= 39.24 N.
Winfred said:
9 years ago
@Thirupathaih, I don't get your solution please explain.
Sarbajit said:
9 years ago
Can we use lamis theorem here?
Gana said:
3 years ago
@All.
First Use Lami's theorem at point B, after finding tension in BC.
Again use Lami's theorem at point C.
First Use Lami's theorem at point B, after finding tension in BC.
Again use Lami's theorem at point C.
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