Help with Static Equilibrium question

In summary, the conversation discusses the problem of finding the minimum angle at which a uniform ladder will not slip when leaning against a frictionless wall. The conversation also mentions the use of the Greek letter theta as the angle in such problems and suggests drawing a free body diagram and applying equilibrium conditions to solve the problem.
  • #1
bjm5295
1
0
If anyone can help me out, i'd really appreciate it. I'm not necessarily looking for the answer, but more how to get to the answer. Thank alot.

A uniform ladder of mass m and length L leans at an angle
theta.gif
against a frictionless wall, Fig. 9-61. If the coefficient of static friction between the ladder and the ground is 0.43, what is the minimum angle at which the ladder will not slip?

9_61.gif


P.S. Whats theta mean? =X For whatever reason I never learned what it means in Physics 1.
 
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  • #2
The Greek letter theta is usually used for the angle in such problems.
For your picture, the moment arm for the horizontal force at top of the ladder
is given by L sin(theta). Draw a Free body diagram and work from that.
 
  • #3
As always, start by identifying all the forces acting on the ladder. Actually draw them on your diagram with proper labels.

Once you've done that, apply the conditions for equilibrium, both translational and rotational.

Hint: What's the maximum possible horizontal force that the floor can exert on the ladder?
 

1. What is static equilibrium?

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

2. How is static equilibrium different from dynamic equilibrium?

Static equilibrium is a state of balance for an object at rest, while dynamic equilibrium is a state of balance for an object in motion. In static equilibrium, all forces are balanced and the object is not moving, while in dynamic equilibrium, the object is moving at a constant speed with all forces balanced.

3. What is the condition for static equilibrium?

The condition for static equilibrium is that the sum of all forces acting on an object must be equal to zero. This means that the forces in both the horizontal and vertical directions are balanced.

4. How do you calculate the force needed to maintain static equilibrium?

To calculate the force needed to maintain static equilibrium, you must first determine the sum of all external forces acting on the object. Then, use the condition for static equilibrium to set up an equation and solve for the unknown force needed to balance the forces.

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

Some real-life examples of static equilibrium include a book resting on a table, a ladder leaning against a wall, and a bridge supporting the weight of cars. In all of these cases, the forces acting on the objects are balanced and the objects are at rest.

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