Double subscript (Force) notation confusion?

Thread starter influx
Start date Mar 30, 2015
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Confusion Force Notation

In summary, double subscript notation is a mathematical notation used to represent variables with multiple indices, commonly used in physics and engineering. It is denoted by placing two subscripts after a variable, such as F<sub>ij</sub> or A<sub>xy</sub>. In physics, it is often used to represent forces, indicating both the direction and the object on which the force is acting. However, it can be confusing due to its use of multiple subscripts and requires a thorough understanding of underlying concepts. It differs from single subscript notation, which is used for variables with only one index and is more commonly used in mathematics. To avoid confusion, careful labeling and consistent notation can be helpful.

Mar 30, 2015

influx

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Shouldn't it be Pdc = 22kN rather than Pcd? I mean the 22kN force arrow is pointing towards C? Because Pdc means the P from D to C no?

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Mar 30, 2015

PhanthomJay

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influx said:

View attachment 81257Pcd is the force of c on d. Pdc is the force of d on c. Free body diagram of cut section 3-3 to D is shown. You can draw FBD of cut section 3-3 to A to get Pdc. Or use Newton 3.

1. What is double subscript notation?

Double subscript notation is a mathematical notation used to represent variables with multiple indices, typically used in physics and engineering. It is denoted by placing two subscripts after a variable, such as F_ij or A_xy.

2. How is double subscript notation used to represent forces?

In physics, forces are often represented by double subscript notation to indicate both the direction and the object on which the force is acting. For example, F_AB represents the force acting on object A due to object B.

3. Why is double subscript notation confusing?

Double subscript notation can be confusing because it may be difficult to distinguish between the two subscripts and remember their meanings. It also requires a thorough understanding of the underlying mathematical concepts to correctly interpret and manipulate the notation.

4. How is double subscript notation different from single subscript notation?

Single subscript notation is used to represent variables with only one index, while double subscript notation is used to represent variables with two indices. Single subscript notation is commonly used in mathematics, while double subscript notation is more common in physics and engineering.

5. Are there any tips for avoiding confusion with double subscript notation?

One helpful tip is to carefully label and define the indices in the notation, and to use consistent and clear notation throughout. It may also be useful to practice manipulating and interpreting double subscript notation in various equations and problems.