Free Body Diagram Solve Problem: Find Force Normal

In summary, the conversation discusses the steps to solve a problem involving a free body diagram, specifically for the case of a window washer applying a force on a brush against a wall. The conversation also clarifies the use of different variables in the equations and confirms that they are in agreement. The only force acting in the horizontal direction is the force of normal, while the force of friction is in the vertical direction.
  • #1
leprofece
241
0
SOLVE THIS PROBLEM View attachment 3071
And this is the figure View attachment 3072

I need the free body diagram because the book solve this problem in this way
the force normsl is n = fcosx
the verticall componente is fsenx = w + miuN
why does the fr is vertical in this case?
 

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  • #2
It'd be more helpful if you were more clear with your question...or fix the typo's in your sentence.

We have to look at the forces in the $x$ and $y$ direction, which you can find by drawing a free-body diagram.

Acting in the $x$ direction, we have the force of normal, and the force applied by the brush in the $x$ direction.
$$F_x=F_{bx}-F_N$$
$$=F(\cos\left({53.1^{\circ}}\right)-F_N=0$$

Similarly for $y$:
$$F_y=F_{by}-F_f-F_g$$
$$=F(\sin\left({53.1^{\circ}}\right))-F_f-F_g$$

What is your question again? :confused:

EDIT: It seems as though you want clarification of the free-body diagram. The window washer applies a force on the brush that is $53.1$ degrees from the horizontal, which we can break into its constituent $x$ and $y$ vectors. We also have the force of gravity acting downwards, and because the brush is pushed against the wall, we also have the force of normal and friction.
 
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  • #3
Rido12 said:
It'd be more helpful if you were more clear with your question...or fix the typo's in your sentence.

We have to look at the forces in the $x$ and $y$ direction, which you can find by drawing a free-body diagram.

Acting in the $x$ direction, we have the force of normal, and the force applied by the brush in the $x$ direction.
$$F_x=F_{bx}-F_N$$
$$=F(\cos\left({53.1^{\circ}}\right)-F_N=0$$

Similarly for $y$:
$$F_y=F_{by}-F_f-F_g$$
$$=F(\sin\left({53.1^{\circ}}\right))-F_f-F_g$$

What is your question again? :confused:

EDIT: It seems as though you want clarification of the free-body diagram. The window washer applies a force on the brush that is $53.1$ degrees from the horizontal, which we can break into its constituent $x$ and $y$ vectors. We also have the force of gravity acting downwards, and because the brush is pushed against the wall, we also have the force of normal and friction.

Yeah I want the drawing or the plot of the free body diagram of the problem That is I required or asked
 
  • #4
Okay! What do you have on your free body diagram so far? :confused:
 
  • #5
\partial \nabla

Here you are my free body diagram as you see we disagree in x axe because you have f cos53 - fr

The book says that fr must be in the vertical
accordin to book in the horizontal there is only one force f cos53 View attachment 3117
 

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  • #6
What are you defining "Fr" to be?

Your textbook isn't in disagreement to what I've said.

I said:

$F_x=F_{bx}-F_N$

$F_x$= zero:

$F(\cos\left({53.1^{\circ}}\right)-F_N=0$

So it simplifies to:

$F_N=F(\cos\left({53.1^{\circ}}\right))$

That is what you have in your first post.

I think you are referring to frictional force with $F_r$. I used $F_f$ instead. Your free body looks correct, and our equations are in agreement. We just used different variables :D
 

What is a free body diagram?

A free body diagram is a visual representation of the forces acting on an object. It shows all the forces acting on the object and their direction, magnitude, and point of application.

How do I solve a problem using a free body diagram?

To solve a problem using a free body diagram, you need to identify all the forces acting on the object and their direction, magnitude, and point of application. Then, you can use Newton's laws of motion to analyze the forces and determine the net force acting on the object.

What is the force normal?

The force normal is the perpendicular force exerted by a surface on an object in contact with it. It is equal in magnitude and opposite in direction to the force exerted by the object on the surface, according to Newton's third law of motion.

How do I find the force normal in a free body diagram?

The force normal can be found by drawing a perpendicular line from the surface to the object's center of mass on the free body diagram. This line represents the force normal, and its magnitude can be calculated using the weight of the object and the angle of the surface.

What are some common mistakes when solving problems using free body diagrams?

Some common mistakes when solving problems using free body diagrams include not correctly identifying all the forces acting on the object, not considering the direction of the forces, and not using the correct equations to calculate the net force.

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