How do I determine the force in each member of the truss?

[Jesus Trinidad]

Homework Statement

Assume that each member of the truss is made of steel
having a mass per length of 4 kg/m. Set p=0 , determine the
force in each member, and indicate if the members are in
tension or compression. Neglect the weight of the gusset plates
and assume each joint is a pin. Solve the problem by assuming
the weight of each member can be represented as a vertical
force, half of which is applied at the end of each member.

Homework Equations

Ʃm=0
Ʃfx=0
Ʃfy=0

The Attempt at a Solution

I don't really know how to start

 

[SteamKing]

The best place to start is to read the problem statement carefully.

There are some directions about setting up the problem. Have you followed these instructions?
It might help you to draw a sketch of the frame as directed. Treat each of the members as a bar, and the bars are connected to each other by pins.

 

[Jesus Trinidad]

reply

The best place to start is to read the problem statement carefully.

There are some directions about setting up the problem. Have you followed these instructions?
It might help you to draw a sketch of the frame as directed. Treat each of the members as a bar, and the bars are connected to each other by pins.

I understand a little bit, someone told me that I have to calculate the weight of the bars first, and I don't really know how to do it, but if someone can tell me how to do that maybe I can do the problem.

 

[SteamKing]

The bars have a mass/unit length of 4 kg/m. If a bar is 4 m long, what is its mass?

 

[rezeew]

this problem.

As a scientist, the first step in determining the force in each member of the truss would be to analyze the given information and identify any relevant equations or principles that can be applied. In this case, we can use the principles of statics to solve for the forces in each member.

The given information states that the truss is made of steel with a mass per length of 4 kg/m. This tells us that the weight of each member can be represented as a vertical force of 4g, where g is the acceleration due to gravity. Since each joint is assumed to be a pin, we can also assume that the forces acting on each joint are only in the horizontal and vertical directions.

To solve for the forces in each member, we can use the equations of statics: Ʃm=0 (sum of moments), Ʃfx=0 (sum of forces in the horizontal direction), and Ʃfy=0 (sum of forces in the vertical direction). We can start by drawing a free body diagram of the truss, labeling the known and unknown forces at each joint.

Next, we can apply the equations of statics to each joint. By setting Ʃm=0, we can solve for the unknown forces at each joint. It is important to note that the weight of each member will contribute to the moments at each joint, so we must include this in our calculations.

Once we have solved for the forces at each joint, we can determine if each member is in tension or compression. If the force is acting away from the joint, then the member is in tension. If the force is acting towards the joint, then the member is in compression.

In conclusion, to determine the force in each member of the truss, we can use the principles of statics and the given information about the truss's material and joint conditions. By setting up and solving the equations of statics for each joint, we can determine the forces in each member and whether they are in tension or compression.