Pulley Traction in Equilibrium

In summary: MENDMENT: In summary, the sum of downward forces exerted at points A and B is 41lbs by the leg. After considering the tension and vertical forces, it is concluded that there is a net horizontal force on the leg that the leg must resist. This can be attributed to the friction between the patient and the bed.
  • #1
Missnomer
1
0

Homework Statement


Sum of downward forces exerted at A and B is 41lbs by the leg, what is the weight attached?
Kpvcb5E.jpg


Homework Equations


None, really...


The Attempt at a Solution


Tension (T) throughout the system must be constant and equal to the weight (W).
I first assumed that the leg was entirely pulled up by B since I thought the force passing A
is going down (wrong since this is in equilibrium) and claimed W = 41sin60, but it's not that simple.

Tension pulls both ways, so there is an upward force at A as well as B.
Since
[itex]ƩF_y = 0[/itex]
[itex]Tsin25 + Tsin60 - 41lb = 0[/itex]
[itex]T = W = 41 / (sin25 + sin60) = 31.0lb[/itex]

But using this value of T in checking horizontal forces, they don't balance out.
What am I missing here, or are my calculations correct and there just is a net horizontal force
on the leg that the leg has to resist?

Thanks in advance :).
 
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  • #2
Missnomer said:

Homework Statement


Sum of downward forces exerted at A and B is 41lbs by the leg, what is the weight attached?
Kpvcb5E.jpg


Homework Equations


None, really...


The Attempt at a Solution


Tension (T) throughout the system must be constant and equal to the weight (W).
I first assumed that the leg was entirely pulled up by B since I thought the force passing A
is going down (wrong since this is in equilibrium) and claimed W = 41sin60, but it's not that simple.

Tension pulls both ways, so there is an upward force at A as well as B.
Since
[itex]ƩF_y = 0[/itex]
[itex]Tsin25 + Tsin60 - 41lb = 0[/itex]
[itex]T = W = 41 / (sin25 + sin60) = 31.0lb[/itex]

But using this value of T in checking horizontal forces, they don't balance out.
What am I missing here, or are my calculations correct and there just is a net horizontal force
on the leg that the leg has to resist?

Thanks in advance :).
The horizontal forces balance if you take into account the friction between the patient and the bed.

AM
 

What is pulley traction in equilibrium?

Pulley traction in equilibrium is a mechanical system in which two or more ropes or cables are connected to a pulley system to distribute force and achieve balance.

How does pulley traction work?

Pulley traction works by using the principles of mechanical advantage and equilibrium to distribute force and achieve balance. As one side of the pulley system is pulled down, the other side will rise, resulting in an equal distribution of force.

What are the types of pulley traction systems?

There are three types of pulley traction systems: fixed, movable, and compound. A fixed pulley has a stationary axle and is used to change the direction of force. A movable pulley has a movable axle and is used to increase mechanical advantage. A compound pulley combines both fixed and movable pulleys for the greatest mechanical advantage.

What are the advantages of using pulley traction in equilibrium?

The main advantage of using pulley traction in equilibrium is that it allows for the distribution of force and the achievement of balance in a mechanical system. This can make it easier to lift heavy objects or to achieve a specific amount of force.

What are some real-life examples of pulley traction systems in equilibrium?

Pulley traction systems in equilibrium can be found in many real-life applications, such as elevators, cranes, and flagpoles. They are also commonly used in weightlifting machines and in sailing to hoist sails and anchor ropes.

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