# A Bar Suspended by Two Vertical Strings

• laxmanic33
In summary, the problem involves a rigid horizontal bar supported by two vertical strings, with an object of mass m2 suspended from a crane at a distance x from the left end of the bar. The goal is to find the tension in string A (T(A)) and the magnitude of the tension in string B (T(B)). To solve for these values, torque equations are set up about the point where each string connects to the bar. The equations involve the weight of the bar and the suspended object, as well as the distance from each string to the point of rotation. The final equations for T(A) and T(B) are found to be 68111.63 and 34056.45, respectively, with a requirement for
laxmanic33

## Homework Statement

A rigid uniform horizontal bar of mass m1 = 85.00 kg and length L = 5.300 m is supported by two vertical massless strings. String A is attached at a distance d = 1.500 m from the left end of the bar and is connected to the top plate. String B is attached to the left end of the bar and is connected to the floor. An object of mass m2 = 2000 kg is supported by the crane at a distance x = 5.100 m from the left end of the bar.

Throughout this problem, positive torque is counterclockwise. Use 9.81 m/s^2 for the magnitude of the acceleration due to gravity.

(1) Find T(A) the tension in string A.
(2) Find T(B) the magnitude of the tension in string B.

## Homework Equations

Ta = (Torque due to weight of bar + Torque due to weight of object) / (l/2)
Tb = Ta*d - m1g(L/2) - m2gx

## The Attempt at a Solution

I got Ta = 68111.63, It says that I am close, rounding error, and it has to be in 4 sig figs.

I got Tb = 34056.45, and no dice with this one.

Last edited:
laxmanic33 said:
Ta = (Torque due to weight of bar + Torque due to weight of object) / (l/2)
Tb = Ta*d - m1g(L/2) - m2gx
I don't understand how you arrived at these equations.

To find Ta, set up a torque equation about the point where string B connects to the bar; To find Tb, set up a torque equation about the point where string A connects to the bar.

Are you using T for both torque and tension? Some units would be a big help to you.

## 1. What is a bar suspended by two vertical strings?

A bar suspended by two vertical strings is a physical system in which a rigid bar is attached to two strings that are hanging vertically from fixed points. The bar can freely rotate about the two strings, allowing for different configurations and movements.

## 2. What are the key components of this system?

The key components of a bar suspended by two vertical strings are the rigid bar, two vertical strings, and fixed points from which the strings are hanging. Additional components may include weights or objects attached to the bar, and any external forces acting on the system.

## 3. What are the forces acting on the bar in this system?

The forces acting on the bar in this system include the tension forces from the strings, the weight of the bar, and any external forces such as gravity or applied forces. The tension forces from the strings are always in opposite directions and act to keep the bar in equilibrium.

## 4. How does the angle of the strings affect the movement of the bar?

The angle of the strings affects the movement of the bar by changing the direction and magnitude of the tension forces acting on it. As the angle of the strings changes, the forces acting on the bar will also change, causing the bar to rotate and potentially move in a different direction.

## 5. What are some real-world applications of a bar suspended by two vertical strings?

A bar suspended by two vertical strings can be found in various real-world scenarios, such as a simple pendulum, a playground swing, or a bridge suspension system. It can also be used in physics experiments to demonstrate concepts such as torque, equilibrium, and rotational motion.

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