Why is the weight going upward? Statics

In summary, the weight in problem 11 of the provided link is pointing upwards instead of downwards because it represents the force acting in the vertical chain connected to point A. This force is denoted as Fae and has the same magnitude as the weight, W. The reason for using this notation is likely to obtain a positive answer in the calculations. It is important to leave a space between a numeric value and its unit symbol, as per the international standard for writing units.
  • #1
asz304
108
0

Homework Statement



http://www.engr.mun.ca/~neil/1010/prob11/set2.pdf"

In the first problem in the link above, why is the weight pointing upwards instead of downwards? I thought there will be a different force prolly called Fae pointing upwards with the weight pointing downwards.

Thanks
 
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  • #2
In the first part I think they just used W to represent the force acting in the vertical chain connected to A.
 
  • #3
But in the calculations, W = mg, where m = 200kg. I still don't get it...
 
  • #4
Yeah I see it now. Not too sure why exactly they did that other than to get a positive answer. If you had W acting downwards, then you'd get the two forces to be negative meaning that the forces act in the opposite direction.
 
  • #5
asz304: W points upward in the FBD of joint A because chain AE applies an upward force on point A, called Fae, where Fae = W. If you wish to write vector Fae, that is fine. And the magnitude of vector Fae is W; i.e., Fae = W.

By the way, always leave a space between a numeric value and its following unit symbol. E.g., 200 kg, not 200kg. See the international standard for writing units (ISO 31-0).
 
  • #6
W must mean Tension in the string. It can't be anything else.
 

1. Why does weight go upward in statics?

In statics, weight goes upward due to the force of gravity. This force is constantly pulling objects towards the center of the Earth, causing them to have a weight that is directed downwards. However, in statics, the weight of an object is balanced by equal and opposite forces, resulting in a net force of zero and causing the weight to appear to be going upwards.

2. What is the difference between weight and mass in statics?

In statics, weight and mass are often used interchangeably, but they are not the same thing. Mass is a measure of the amount of matter in an object, while weight is a measure of the force of gravity acting on an object. In statics, the weight of an object is dependent on its mass, but it is also influenced by external forces such as support and friction.

3. Can weight go downward in statics?

In statics, weight can appear to go downward if the object is not in equilibrium. This means that the net forces acting on the object are not balanced, and there is a resultant force causing the object to accelerate in a certain direction. In this case, the weight may be directed downwards due to the force of gravity, but there are other forces at play causing the object to move in a different direction.

4. How does the position of an object affect its weight in statics?

In statics, the position of an object does not affect its weight. The weight of an object is determined by its mass and the force of gravity, which are both constant regardless of its position. However, the position of an object can affect the distribution of weight and the forces acting on it, which can impact its stability and equilibrium in statics.

5. Why is it important to understand weight in statics?

Understanding weight in statics is crucial for accurately analyzing and predicting the behavior of objects under different forces and conditions. In engineering and design, it is essential to consider the weight of structures and objects to ensure their stability and safety. In physics, weight is a fundamental concept in understanding the behavior of objects in relation to gravity and other forces. Overall, understanding weight in statics allows us to make informed decisions and calculations for various applications.

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