Direction of force exerted by ground for the ladder problem

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SUMMARY

The discussion focuses on the static equilibrium of a ladder leaning against a frictionless wall, specifically examining the direction of the force exerted by the ground on the ladder. The hypothesis presented suggests that the force direction aligns with the ladder's angle, θ, which varies from vertical to horizontal. Participants emphasize solving the equations of static equilibrium, equating the sum of forces and torques to zero, to confirm or disprove this hypothesis. The analysis is grounded in classical mechanics principles, particularly the behavior of forces in static systems.

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  • Familiarity with free-body diagrams
  • Basic mathematical skills for solving equations
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  • Learn to construct and analyze free-body diagrams
  • Explore the equations of motion for rigid bodies
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ddcz
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This question pertains to the classic ladder-leaning-against frictionless wall scenario. The system is in static equilibrium. The ladder is thin and can be assumed to be made of a homogeneous material so that the center-of-mass lies at the geometric center.

The forces in this scenario is well-known, and diagrammed as follows. This type of problem can be solved by equating the sum of forces and torques to zero at any and all points, as is commonly done in static equilibrium problems.
Pic14.jpg


My question is: Is the direction of the force exerted by the ground on the ladder aligned with the ladder itself? That is, is the force exerted by the ground on the ladder in the direction \theta, as shown in the diagram?

This hypothesis seems plausible to me, because as theta becomes large (ladder is almost vertical), the force in question is also almost at 90 degrees. As theta approaches zero (ladder is almost horizontal), there is a large horizontal component, so the force is almost horizontal (to the right).

Could anyone confirm or disprove my hypothesis?
 
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ddcz said:
Is the direction of the force exerted by the ground on the ladder aligned with the ladder itself? That is, is the force exerted by the ground
Suppose it were. Consider moments about the mid point of the ladder.
 
ddcz said:
This question pertains to the classic ladder-leaning-against frictionless wall scenario. The system is in static equilibrium. The ladder is thin and can be assumed to be made of a homogeneous material so that the center-of-mass lies at the geometric center.

The forces in this scenario is well-known, and diagrammed as follows. This type of problem can be solved by equating the sum of forces and torques to zero at any and all points, as is commonly done in static equilibrium problems.
Pic14.jpg


My question is: Is the direction of the force exerted by the ground on the ladder aligned with the ladder itself? That is, is the force exerted by the ground on the ladder in the direction \theta, as shown in the diagram?

This hypothesis seems plausible to me, because as theta becomes large (ladder is almost vertical), the force in question is also almost at 90 degrees. As theta approaches zero (ladder is almost horizontal), there is a large horizontal component, so the force is almost horizontal (to the right).

Could anyone confirm or disprove my hypothesis?

Why not solve the equations and see for yourself?
 

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