Trouble with a classic statics problem

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In summary, the conversation discusses a problem involving three weights and three pulleys, where the angles at the central pulley are unknown and the masses are 3 kg and 2 kg each. The goal is to find the angles at static equilibrium. The attempt at a solution involves breaking down force components and using the equations for tension and acceleration. The problem was eventually solved by considering the tension in the system and finding the equilibrium for it.
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Homework Statement


You are given three weights and 3 pulleys. Each mass hangs below a single pulley, and the pulleys are all connected by strings. The middle weight is 3 kg, the other two are each 2 kg. There are two unknown angles at the central pulley, with respect to the horizontal such that the lines connecting to the other pulleys would form the hypotenuse of a right triangle.

Essentially it's this: http://forums.xkcd.com/viewtopic.php?f=18&t=45987 only the angles are unknown, and the masses are changed to what I have listed above.

I have to find the angles if the system is at static equilibrium.

Homework Equations


None

The Attempt at a Solution


I tried breaking it down into force components, but something isn't right.

I figured the tensions would be 2g, 2g, and 3g all told, and that I'd need the components for the "v" shaped lines. I ended up with 2gcos(theta)-3gcos(theta)+3gcos(theta)-2gcos(theta) for the sum of the x components, and 4gsin(theta)-3gsin(theta) for the y components, but this does not work out correctly. I am now completely lost, and have no idea how to properly set up the force diagram to solve the equation.
 
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I solved the problem. I remembered that tension in the system causes acceleration in a given direction if the force (in this case, just the mass) of the system is greater (or lesser) than the tension. So I found the equilibrium for that.
 

FAQ: Trouble with a classic statics problem

What is a classic statics problem?

A classic statics problem is a type of physics problem that involves analyzing the forces acting on a stationary object or system. These problems typically involve finding the equilibrium of the object or system and determining the values of the forces acting on it.

Why is it important to study statics problems?

Studying statics problems is important because it helps us understand how forces interact with objects and systems in a state of equilibrium. This knowledge is crucial for designing and analyzing structures, machines, and other engineering systems.

What are some common challenges when solving a classic statics problem?

Some common challenges when solving a classic statics problem include correctly identifying and drawing all the forces acting on the object or system, choosing the appropriate coordinate system, and correctly applying Newton's laws of motion and the equations of static equilibrium.

What are some strategies for solving a classic statics problem?

Some strategies for solving a classic statics problem include drawing a clear and accurate free-body diagram, breaking down complex systems into simpler sub-systems, and using trigonometric functions to decompose forces into their components.

What are some real-world applications of statics problems?

Statics problems have a wide range of real-world applications, including designing and analyzing bridges, buildings, and other structures, determining the stability of objects and systems, and calculating the forces acting on aircraft and other vehicles. Statics is also important in fields such as biomechanics, where it is used to analyze the forces acting on the human body and design prosthetic devices.

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