Torque on a Massful Beam with Load

In summary, the question involves calculating the magnitude of torque on a steel beam with a length of 2.90m and mass of 390kg, with a construction worker weighing 71kg standing at the far end. Using the equation Torque = mgl, it is important to consider the center of gravity and draw a free-body diagram to correctly express the net torque equations. The final answer for the magnitude of torque is 13101.62 N*m, found by summing up the torque of the beam and the person standing at the edge.
  • #1
amdma2003
7
0
This is the problem I have with the question with a beam with mass.

Homework Statement


A 2.90 -m-long, 390 kg steel beam extends horizontally from the point where it has been bolted to the framework of a new building under construction. A 71.0 kg construction worker stands at the far end of the beam. What is the magnitude of the torque about the point where the beam is bolted into place?


Homework Equations


The equation that I used:
Torque = mgl
where
m = mass
g = 9.8
l = length

As provided by my professor.

The Attempt at a Solution


Since the beam is bolted at the edge, and is horizontal, m=390, and l=2.9
In addition, there is a load applied to the edge of the beam so:
(390 + 71)9.8 * 2.9 = torque

Torque is 13101.62

However, that is wrong, can someone tell me why and what I am doing wrong? Thanks
 
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  • #2
How do you express your equation as sum of all the torque? Also is the length value same for the beam and the person if you draw a freebody diagram? Another words, is the man standing in the middle or the end? Did you take consideration center of gravity? You need to learn to draw things out, put the arrows pointing down at the right places, it will help you visulize where the force is acting so you can correctly express it in your Net torque equations
 
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  • #3
The sum of the torque is T1+T2, and the person is standing at the edge of the beam. I do know the torque of the person standing at the edge, which is 2.9 * 71 * 9.8 = 2017.82 however, I do not know how to find the torque of the beam.
 
  • #4
Your stealbeam assuming that it is uniform in mass, it should have its downward force eactly in the middle, think of the stealbeam as a point particle, and all the mass is centered at the center :) that will give you its torque. And the person is standing at the edge at that distance, there is another downward force there. So sum up all the Torque.
 
Last edited:
  • #5
Ok, thanks. The torque of the beam is mgl/2. Thats what I forgot.
 

1. What is torque on a massful beam with load?

Torque on a massful beam with load refers to the rotational force that is applied to a beam when a load is placed on it. This force causes the beam to rotate around an axis, and is typically measured in units of Newton-meters (Nm).

2. How is torque on a massful beam with load calculated?

The formula for calculating torque on a massful beam with load is T = F x d, where T represents torque, F represents the force applied to the beam, and d represents the distance from the axis of rotation to the point where the force is applied. This formula applies to both single loads and multiple loads on a beam.

3. What factors can affect torque on a massful beam with load?

The two main factors that can affect torque on a massful beam with load are the magnitude of the force applied and the distance from the axis of rotation. The greater the force and the farther the distance, the greater the torque will be. Additionally, the weight and distribution of the load can also impact the torque on the beam.

4. How does torque on a massful beam with load impact the structural integrity?

Excessive torque on a massful beam with load can cause it to bend or break, depending on the strength of the material. It is important to carefully consider the amount and placement of the load on a beam to ensure that it can withstand the torque forces without compromising its structural integrity.

5. Can torque on a massful beam with load be reduced or eliminated?

In some cases, it may be possible to reduce or eliminate torque on a massful beam with load by redistributing the load or changing the location of the axis of rotation. Additionally, using support structures such as braces or trusses can also help to reduce the amount of torque on a beam.

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