Part A Three chains act on the bracket such that they create a resultant force h
ID: 1526116 • Letter: P
Question
Part A
Three chains act on the bracket such that they create a resultant force having a magnitude of 440 lb . If two of the chains are subjected to known forces, as shown,(Figure 1) determine the angle of the third chain measured clockwise from the positive x axis, so that the magnitude of force F in this chain is a minimum. All forces lie in the x-y plane. Hint: First find the resultant of the two known forces. Force F acts in this direction.
Express your answer with the appropriate units.
....
(90 was a wrong answer)
Part B
What is the magnitude of F?
Express your answer with the appropriate units.
=....
200 lb 300 lbExplanation / Answer
Net foce = 440 lb
FR1 = (300^2 +200^2 +2*300*200*cos(120))^0.5
FR1 = 264.6 lb
from sine law:
(sin(30+))/200 = sin(60)/264.6
= 10.9 degrees
(b) when F is along FR1 , F will be minimum to create the resultant force
FR = FR1 +F
440 = 264.6 + F
F = 175.4 lb