# I with some Equilibrium problems

• SalamanderGod
In summary, the conversation discusses a problem involving a traffic light hanging from a structure. The pole has a length of 7.5 m and a mass of 8.0 kg, while the light has a mass of 12.0 kg. The goal is to determine the tension in the horizontal cable CD and the vertical and horizontal components of the force exerted by the pivot A on the pole. The weight of the pole and light are given, along with the angle between them. The conversation also mentions taking moments about point A to simplify the problem.
SalamanderGod
#2: A traffic light hangs from a structure as shown in Fig. 9-60. The uniform aluminum pole AB is 7.5 m long and has a mass of 8.0 kg. The mass of the traffic light is 12.0 kg. Determine the tension in the horizontal massless cable CD, and the vertical and horizontal components of the force exerted by the pivot A on the aluminum pole.
http://img457.imageshack.us/my.php?image=fig960xg6.png

Can I just get help on this one? I figured out the rest.

Last edited:
Anyone want to help?

One is expected to show ones efforts. Let's start with what you know...

Well, I know that the weight of the pole is 78.4 N and the light's weight is 117.6N, and that the light makes a 53degree angle with the pole, and since the sum of torques has to be 0, I need to separate the weights into their x and y components... the problem with that was I got stuck when I realized that I didn't know what the x value of the point Ft acts on was... Is it safe to assume that since sum of torques is 0, that Ft and the force exerted by A are aqual but opposite in direction?

I would recommend taking moments about point A, then you don't need to worry about any forces acting through A.

"taking moments"? do you mean setting A as the origin for torque?

SalamanderGod said:
"taking moments"? do you mean setting A as the origin for torque?
Yes, apologies; the jargon can vary from course to course.

ok, thanks!

## 1. What is equilibrium in a scientific context?

Equilibrium in a scientific context refers to a state of balance or stability in a system, where there is no net change or movement. This can apply to a wide range of systems, from chemical reactions to physical forces and even ecosystems.

## 2. How is equilibrium achieved?

Equilibrium is achieved when the forces acting on a system are balanced, meaning there is no net force causing movement or change. This can be achieved through a variety of processes, such as adjusting the concentration of reactants in a chemical reaction or changing the temperature and pressure of a system.

## 3. What are the different types of equilibrium?

There are three main types of equilibrium: stable, unstable, and neutral. In stable equilibrium, the system returns to its original state after a small disturbance. In unstable equilibrium, the system moves away from its original state after a small disturbance. In neutral equilibrium, there is no change in the system regardless of any small disturbance.

## 4. What factors can affect equilibrium?

Several factors can affect equilibrium, including temperature, pressure, concentration, and the presence of catalysts. Changes in any of these factors can shift the equilibrium position of a system, resulting in changes to the amount of products and reactants present.

## 5. How do we calculate equilibrium constants?

Equilibrium constants are calculated using the concentrations of reactants and products at equilibrium. The equilibrium constant expression is written as [products] / [reactants], where the concentrations are raised to the power of their respective coefficients in the balanced chemical equation. The value of the equilibrium constant can tell us about the extent of the reaction and the relative amounts of products and reactants at equilibrium.

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