Determine the magnitude of the resultant force

In summary, the problem is asking to find the magnitude of the resultant force acting along the positive u axis, given that F_B = 5kN. Using the equations F_{Rx} = 3 + 5cos\theta and F_{Ry} = 5sin\theta, we can set them equal to \sqrt{3} and solve for \theta. However, since the question is asking for the resultant force, we can use a combination of these equations to find the value of F_R without explicitly solving for \theta. It is important to keep track of the variable being asked for and not let it disappear when combining equations.
  • #1
Precursor
222
0
Homework Statement
If [tex]F_{B} = 5kN[/tex] and the resultant force acts along the positive u axis, determine the magnitude of the resultant force.

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The attempt at a solution

[tex]F_{Rx} = F_{R}cos 30[/tex]

[tex]F_{Ry} = F_{R}sin 30[/tex]

[tex]F_{Rx} = 3 + 5cos\theta[/tex]

[tex]F_{Ry} = 5sin\theta[/tex]

Therefore, [tex]\frac{3 + 5cos\theta}{5sin\theta} = \sqrt{3}[/tex]

Is this correct so far? I don't know how to isolate [tex]\theta[/tex]
 
Last edited:
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  • #2
What variable is the problem asking you to find?
 
  • #3
diazona said:
What variable is the problem asking you to find?

It is asking for the resultant force which acts along the u axis.
 
  • #4
Precursor said:
It is asking for the resultant force which acts along the u axis.
That is right so you don't have to find [tex] \theta [/tex]
 
  • #5
Winzer said:
That is right so you don't have to find [tex] \theta [/tex]

Then how would I go about finding the resultant force? Using a combination of the equations I posted in my attempt?
 
  • #6
Yep. I asked which variable the question was asking for for a reason; make sure you know which variable you need to find the value of and don't let it disappear when you combine the equations.
 
  • #7
diazona said:
Yep. I asked which variable the question was asking for for a reason; make sure you know which variable you need to find the value of and don't let it disappear when you combine the equations.

But I still don't see how I can solve for the resultant force without first solving for theta. Am I missing something?
 

Related to Determine the magnitude of the resultant force

What is meant by the magnitude of the resultant force?

The magnitude of the resultant force is the overall strength or intensity of the combined forces acting on an object. It is a numerical value that represents the overall effect of all the forces acting on the object.

How is the magnitude of the resultant force calculated?

The magnitude of the resultant force can be calculated using the Pythagorean theorem, where the magnitude is the square root of the sum of the squares of the individual forces. It can also be calculated using vector addition, where the magnitudes and angles of the individual forces are taken into account.

Why is it important to determine the magnitude of the resultant force?

Determining the magnitude of the resultant force is important because it helps us understand the overall effect of all the forces acting on an object. This information is crucial for predicting the motion and behavior of the object.

What factors can affect the magnitude of the resultant force?

The magnitude of the resultant force can be affected by the magnitudes and directions of the individual forces, as well as the angle at which they act. The presence of friction or other external forces can also impact the magnitude of the resultant force.

How can the magnitude of the resultant force be used in real-world applications?

The magnitude of the resultant force has many practical applications, such as calculating the weight-bearing capacity of structures, determining the thrust and lift of aircraft, and predicting the trajectory of projectiles. It is also used in fields such as engineering, physics, and sports science.

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