Rotational Equilibrium Question

AI Thread Summary
A bar of uniform density, supported by two ropes with tensions T1 and T2, is tilted at an angle θ, with a mass M placed at a distance l from T1. The problem involves calculating the distance l in terms of the bar's length L, given specific values for mass and angle. The net torque and force equations are established, but the challenge arises from having two equations with three unknowns. The key is to express the vertical component of the net force and focus on finding l as a multiple of L rather than determining L itself. The user successfully resolved the issue with guidance on the problem's requirements.
Joshd99

Homework Statement


A bar of uniform density, length L, and mass m is suspended by two ropes of tensions T1 and T2 at either extremity of the bar. The bar is tilted such that it makes an angle θ with the ropes. A mass M is resting at a distance l from T1.
https://i.imgur.com/vLlAJbe.png

If m=17.7kg, M=12.4kg, the angle θ=24.9, and the magnitude T1 is twice as large as T2, what is the distance l in units of L?

Homework Equations


Tnet = 0
Fnet = 0

The Attempt at a Solution


I started off by setting the pivot point at the end of the bar on the side of T1, and therefore the net torque equation should become Mg*l + mg*L/2 - Ft2sinθ*L = 0.

Next I set the net force equation as Ftcosθ + 2*Ftcosθ - mg - Mg = 0

Unsure of how to solve the question as I'm stuck with 2 equations and 3 unknowns L l and Ft
 
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What is Ft? Just write an expression for the vertical component of the net force and set it equal to zero.

On edit: You're not supposed to find L. The problem is asking you to find ##l## in units of L. That means finding ##l## as some number times L.
 
Last edited:
kuruman said:
What is Ft? Just write an expression for the vertical component of the net force and set it equal to zero.

On edit: You're not supposed to find L. The problem is asking you to find ##l## in units of L. That means finding ##l## as some number times L.
thanks for the reply, figured it out with what you mentioned in the edit :)
 
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