How Can the Minimum Distance x for Load P on a Movable Bracket Be Determined?

In summary: When I do that, everything else usually falls into place.In summary, the movable bracket shown may be placed at any height on the 50-mm-diameter pipe. If the coefficient of static friction between the pipe and bracket is 0.30, determine the minimum distance x at which the load P can be supported. Assume that the bracket is weightless.
  • #1
hp-p00nst3r
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0

Homework Statement


The movable bracket shown may be placed at any height on the 50-mm-diameter pipe. If the coefficient of static friction between the pipe and bracket is 0.30, determine the minimum distance x at which the load P can be supported. Assume that the bracket is weightless.
http://img396.imageshack.us/img396/18/220selftest27vo7.gif

Homework Equations


Sum of Forces and Moments = 0 for equilibrium
F_f = uN

The Attempt at a Solution


I got stuck after getting the equilibrium equations. Too many variables and not enough equations.
http://img254.imageshack.us/img254/7721/mech220fbd7mj4.jpg
 
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  • #2
Your FBD is oversimplified. The friction force acts at points A and B. The 50 mm diameter of the pipe must be accounted for. The friction force at A is acting on the left side of the pipe, and at B on the right side of the pipe. Also, the normal force N is related to the horizontal force components.
 
  • #3
Is this what you are talking about?
With these equations I still have 4 unknowns and 3 equations
http://img381.imageshack.us/img381/9784/mech220fbd7xu5.jpg
 
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  • #4
A numnerical answer is not possible since the loading P is not known. Write your answer in terms of P.
 
  • #5
There are 5 choices for the answer and they are all numerical answers
A. 0.025 m
B. 0.1667 m
C. 0.1920 m
D. 0.200 m
E. 0.217 m

According to the key, the answer is B
 
  • #6
I hate it when that happens...

The answer key is correct. You have the equations that you need, except that x is measured from the centerline of the pipe, and so in eqn 3, the term on the left in parenthesis should be (x + 0.025).

Sub for NA in eqn 2 from eqn 1. Sub from that result for P into eqn 3. NB will cancel out; solve for x and you should get answer B.
 
  • #7
Thank you very much.
I think the FBD part was the hardest part of the question. But once that is in place, everything falls together really well. I tend to have trouble with the FBD part and trying to think about how each force goes.
 

FAQ: How Can the Minimum Distance x for Load P on a Movable Bracket Be Determined?

What is a free body diagram?

A free body diagram is a visual representation of an object or system that isolates all external forces acting on it. It is used to analyze the forces in a system and determine if it is in equilibrium.

What is equilibrium?

Equilibrium is a state in which an object or system has balanced forces acting on it, resulting in no net force and no acceleration. This means the object will either remain at rest or continue moving at a constant velocity.

How do you draw a free body diagram?

To draw a free body diagram, you must first identify the object or system and all the external forces acting on it. Then, draw a dot to represent the object and draw arrows to represent each force acting on the object. The length and direction of the arrows should correspond to the magnitude and direction of the force.

What are the key components of a free body diagram?

The key components of a free body diagram include the object or system being analyzed, all external forces acting on the object, labeled arrows representing the magnitude and direction of each force, and a coordinate system to show the orientation of the object.

Why are free body diagrams important in science?

Free body diagrams are important in science because they allow us to analyze and understand the forces acting on an object or system. They are a crucial tool in physics and engineering, helping us to solve problems related to motion, forces, and equilibrium.

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