Static Equilibrium, new to this subject, help please?

In summary, a student is struggling with a statics problem involving a beam attached to a wall with a hinge and supported by a cable. They are trying to find the horizontal component of the force exerted by the hinge on the beam. The student attempted to solve the problem using trigonometry and torque equations, but is unsure of their approach and is asking for help.
  • #1
jcfor3ver
30
0

Homework Statement



So I have looked at several ladder example problems, (the most basic for statics), but was given a problem by my professor that has me a little stumped. This is day 2 of learning for me and I am caught up, here's the problem:

A 30.8 kg beam is attached to a wall with a hinge and its far end is supported by a cable. The angle between the beam and the cable is 90o. If the beam is inclined at an angle of = 10.4o with respect to horizontal, what is the horizontal component of the force exerted by the hinge on the beam? (Use the `to the right' as + for the horizontal direction.)

I uploaded a pic so everyone can see the situation.



Homework Equations



Well any basic trig knowledge, cos, sin, and tan.

Torque=Force*distance.




The Attempt at a Solution



L=length
Theta
Nc= normal force by the cable
mg= mass times gravity
Fby-forcy by beam in y
Fbx= force by beam in x

I tried breaking it into letter variables first and solving that way instead of plugging in numbers the whole time.

I know I should set my Net force in all directions to zero.

I Set the force by the cable on the wall equal to the force of the beam in the x direction.
Then for the y direction the force of the beam (Fby)= mg

Then for torque I did T=-1/2Lcostheta(mg)+NcLsintheta

But I am really confused on how to set all of this up. Please help? I resulted with Nc=m/2*cottheta
But The number I entered gave me a wrong answer for the computer. What am I doing wrong?
 

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  • #2
jcfor3ver said:
Then for torque I did T=-1/2Lcostheta(mg)+NcLsintheta

The cable is perpendicular to the beam, so the torque of Nc is simply Nc*L.

ehild
 

Related to Static Equilibrium, new to this subject, help please?

1. What is static equilibrium?

Static equilibrium is a state in which an object is at rest and all of the forces acting on it are balanced. This means that the object will not accelerate or move in any direction.

2. How is static equilibrium different from dynamic equilibrium?

Static equilibrium is when an object is at rest, while dynamic equilibrium is when an object is moving at a constant velocity. In dynamic equilibrium, the forces acting on an object are still balanced, but the object is in motion.

3. What are the conditions for an object to be in static equilibrium?

There are two conditions for an object to be in static equilibrium: the sum of all forces acting on the object must be zero, and the sum of all torques (rotational forces) acting on the object must also be zero.

4. How do I calculate the forces and torques in a system to determine static equilibrium?

To calculate the forces and torques in a system, you will need to use Newton's laws of motion and the principles of torque. You will need to identify all the forces acting on the object and their directions, and then use equations to determine if they are balanced or not.

5. What are some real-life examples of static equilibrium?

Some examples of static equilibrium in everyday life include a book sitting on a table, a tree standing upright, and a person holding a cup without it falling. In all of these cases, the forces acting on the object are balanced, resulting in a state of rest.

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