Calculate the Tension and Angular Acceleration in Log After Release

I don't know if that's the correct way to do it.In summary, the problem involves a 69-lb log being used as a battering ram and being supported by two cables. The goal is to calculate the initial tension induced in each cable and the corresponding angular acceleration of the cables when the log is released from rest. The attempt at a solution involves using the sum of forces in the x and y directions, assuming acceleration is equal to 0, and taking the moment about the center of the beam. The distances used are the perpendicular distances from the tensions, and the inertia may need to be calculated. However, the poster has managed to solve the problem using a normal and tangential coordinate system.
  • #1
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Homework Statement


The uniform 69-lb log is supported by the two cables and used as a battering ram. If the log is released from rest in the position shown, calculate the initial tension induced in each cable immediately after release and the corresponding angular acceleration α of the cables.


Homework Equations





The Attempt at a Solution



I tried first by summing the forces in the x and y directions

ƩFx: max = TAcos(θ) + TBcos(θ)

ƩFy: may = -mg + TAsin(θ) + TBsin(θ)

I assumed that ax and ay are equal to 0 and then I took these two equations and tried to solve them by using the matrix function on my calculator, but it doesn't work.

I'm now trying to take the moment about the center of the beam

The distances I have used should be the perpendicular distances from the tensions

ƩMG: = Iα = -TA((d+e)/s)sin(θ) + TB((d+e)/2 - d)sin(θ)

but I'm not sure how to calculate the inertia, or if I need to calculate it at all.

Any advice would be greatly appreciated.
 

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  • #2
I've managed to figure it out using a normal and tangential coordinate system,
 

Related to Calculate the Tension and Angular Acceleration in Log After Release

1. What is the formula for calculating tension in a log after release?

The formula for calculating tension in a log after release is T = (M + m)a, where T is the tension, M is the mass of the log, m is the mass of the object attached to the log, and a is the angular acceleration.

2. How do you determine the angular acceleration of a log after release?

The angular acceleration of a log after release can be determined by using the formula a = (T - Mg)/I, where T is the tension, M is the mass of the log, g is the acceleration due to gravity, and I is the moment of inertia of the log.

3. What is the moment of inertia of a log?

The moment of inertia of a log is a measure of its resistance to rotational motion. It is calculated by taking into account the mass distribution and shape of the log.

4. How does the mass of the object attached to the log affect the tension and angular acceleration?

The mass of the object attached to the log affects the tension and angular acceleration by increasing the overall mass and therefore requiring more force to accelerate the log. This results in a higher tension and a lower angular acceleration.

5. Are there any other factors that can affect the tension and angular acceleration in a log after release?

Yes, there are other factors that can affect the tension and angular acceleration in a log after release, such as the length and thickness of the log, the angle at which it is released, and any external forces acting on the log. These factors may alter the moment of inertia and therefore impact the tension and angular acceleration calculations.

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