Solve Broken Leg & Pulleys: Find Weight W

In summary, the problem is to find the weight W attached to the lower puller when the total downward force exerted at points A and B by the leg is 38N. The equations used involve breaking the force into components at different points, and ultimately solving for T and mg. However, there may be missing components and it is unclear why the force at point A is being broken into components.
  • #1
stunner5000pt
1,461
2

Homework Statement


assume that the total downward force exerted at A & B by the leg is 38N. find the weight W, attached on the lower puller

Homework Equations


please see attached diagram

The Attempt at a Solution


[/B]
i have written roman numerals to help determine which equation refers to which point

at point I
[tex] W = T [/tex]at point II
in the X direction
[tex] T \cos 25 + F_{1} = F_{A} cos \theta [/tex]
in the y direction

[tex] T \sin 25 = F_{A} \sin \theta [/tex]

at point III
in the X direction
[tex]0=T \cos 20 +T \cos 25 [/tex]

in the Y direction

[tex] T \sin 20 + T \sin 25 [/tex]

at point IV

in the X direction

[tex] T \cos 20 + T \cos 60 = 0 [/tex]in the Y direction

[tex] -T \sin 20 - T\sin 60 = 0 [/tex]

And that the end of this, can we say that T = 38N?

Please let me know if all the equations are correct?
Thank you for your input and assistance!
 

Attachments

  • leg question.jpg
    leg question.jpg
    23.6 KB · Views: 464
Physics news on Phys.org
  • #2
stunner5000pt said:

Homework Statement


assume that the total downward force exerted at A & B by the leg is 38N. find the weight W, attached on the lower puller

Homework Equations


please see attached diagram

The Attempt at a Solution


[/B]
i have written roman numerals to help determine which equation refers to which point

at point I
[tex] W = T [/tex]at point II
in the X direction
[tex] T \cos 25 + F_{1} = F_{A} cos \theta [/tex]
in the y direction

[tex] T \sin 25 = F_{A} \sin \theta [/tex]

at point III
in the X direction
[tex]0=T \cos 20 +T \cos 25 [/tex]

in the Y direction

[tex] T \sin 20 + T \sin 25 [/tex]

at point IV

in the X direction

[tex] T \cos 20 + T \cos 60 = 0 [/tex]in the Y direction

[tex] -T \sin 20 - T\sin 60 = 0 [/tex]

And that the end of this, can we say that T = 38N?

Please let me know if all the equations are correct?
Thank you for your input and assistance!
Well I'm not sure of this problem but if the lower leg is horizontal and takes only an axial pulling force F1 , then draw the FBD of the pulley at the foot and sum vertical forces to solve for T and thence mg. F-a is given I think as a vert force of 38 N at A so I don't know why you are breaking it into components. You are also missing a tension force in your equation at that pulley.
 

FAQ: Solve Broken Leg & Pulleys: Find Weight W

What causes a broken leg?

A broken leg, also known as a fractured leg, usually occurs due to direct trauma, such as a fall or a sports injury. It can also be caused by repetitive stress or overuse, weakening the bone over time.

How do you know if a leg is broken?

Signs of a broken leg include severe pain, swelling, bruising, and difficulty or inability to put weight on the affected leg. In some cases, the broken bone may even be visible through the skin.

Can a broken leg heal on its own?

In some cases, a broken leg can heal on its own, especially if the fracture is small and stable. However, it is important to seek medical attention to ensure proper healing and prevent any complications.

What is the purpose of pulleys in treating a broken leg?

Pulleys are commonly used in physical therapy for broken legs to help with range of motion exercises and to gradually increase weight bearing on the affected leg. This can aid in the healing process and prevent stiffness or muscle atrophy.

How do you calculate the weight needed to use with pulleys for a broken leg?

The weight needed to use with pulleys for a broken leg is typically determined by a physical therapist or doctor based on the individual's specific injury and progress. It is important to follow their instructions and not exceed the recommended weight to avoid further injury.

Back
Top