Free body diagram drawing for a two force members on machine

In summary, when a 2 lb force is applied to the handles of the brad squeezer, it pulls in the smooth rod AB. The force P exerted on each of the smooth brads at C and D can be determined using the equations ##\sum F_x=0##, ##\sum M=0##, and ##\sum F_y=0##. The free body diagram shows that P is opposite to the initial force applied, but solving the equations yields a different result. It is important to carry units along and be careful when using English/Imperial units.
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Homework Statement


When a force of 2 lb is applied to the handles of the brad squeezer, it pulls in the smooth rod AB. Determine the force P exerted on each of the smooth brads at C and D

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Homework Equations


##\sum F_x=0##
##\sum M=0##
##\sum F_y=0##

The Attempt at a Solution


I drew a free body diagram of Members EA with the initial force applied. Since A and B are two force members, ##F_{AB}## is drawn opposite direction in free body diagram BCD. However when I solve the the equations I get that P is opposite to the Free body diagram drawn. Why is that is there some mistake?[/B]

Moments about ##E## yields ##M_E=2\cdot 2-F_{AB}=0## so ##F_{AB}=4##
In second FBD, I get that ##P=-2##there must be some mistake in this?
 

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  • #2
Wow, I thought I was the only one who ever used English/Imperial units any more.

The sum of the torques about a given axis must be zero.

Taks care, and carry your units along.
 

FAQ: Free body diagram drawing for a two force members on machine

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 external forces acting on the object as arrows, with the direction and magnitude of each force indicated.

How do I draw a free body diagram for a two force member on a machine?

To draw a free body diagram for a two force member on a machine, start by identifying the object and all the external forces acting on it. Draw a dot to represent the object and draw arrows to represent each force, making sure to label the direction and magnitude of each force.

Why is it important to draw a free body diagram for a two force member on a machine?

Drawing a free body diagram allows you to visually analyze the forces acting on an object and determine the net force. This is essential for understanding how the object will behave and how different forces may affect its motion.

Can a free body diagram be drawn for non-physical or imaginary objects?

Yes, a free body diagram can be drawn for any object, whether it is physical or imaginary. The purpose of a free body diagram is to analyze the forces acting on an object, regardless of its physical existence.

Are there any conventions or rules for drawing a free body diagram for a two force member on a machine?

Yes, there are a few conventions for drawing a free body diagram. The object should be represented by a dot, forces should be represented by arrows, and the arrows should be drawn in the direction of the force with the magnitude labeled. It is also important to include a reference frame and make sure all forces acting on the object are accounted for.

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