Determining resultant force direction when x-component is positive

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foo9008
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Homework Statement


i am confused about the direction of resultant force . in the working ,it's clear that the author taking to the right as positive ,
for the force component along x-axis , we have -Fx , but , in the calclulation , we gt positive 32230N , so the resultant force of x-component is to the left(32230N ) , am i correct ?

Homework Equations

The Attempt at a Solution

 
Attachments
  • Diagram of a pipe bend turning 45 degrees, with section 1 at the inlet labelled P1 and A1 and section 2 at the outlet labelled P2 and A2, with velocity V2 shown along the outlet.
    1.PNG
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  • Handwritten-style worked solution applying Bernoulli's equation between points 1 and 2 to find P2 = 1.23 x 10^5 N/m^2, then the x-direction momentum balance giving Fx = 32260 N.
    2.PNG
    12.3 KB · Views: 443
  • Handwritten worked calculation of a fluid-jet force: Fy = 7970 N, F = sqrt(32260^2 + 7970^2) = 33230 N = 33 kN, and direction theta = tan^-1(Fx/Fy) = 13.9 degrees to horizontal.
    3.PNG
    6.7 KB · Views: 448
Chestermiller said:
The author is taking Fx to be positive if the force is pointing is the negative x direction.
ia my idea correct / the resultant force act to the left ?
 
foo9008 said:
what do you mean ?
In vector terms, the x component of the force ##\vec{F}## is taken to be ##-F_x\vec{i}_x##, where ##\vec{i}_x## is the unit vector in the positive x direction.
 
Chestermiller said:
In vector terms, the x component of the force ##\vec{F}## is taken to be ##-F_x\vec{i}_x##, where ##\vec{i}_x## is the unit vector in the positive x direction.
is my idea correct ? the resultant force act to the left ?
 
foo9008 said:
is my idea correct ? the resultant force act to the left ?
Yes. It is positive to the left.
 
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