# Strengths Homework

1. Sep 16, 2009

### mustang1988

1. The pin-connected truss supports loads of 10kN and 35kN. The allowable stress is 150MPa in tension and 75MPa in compression. Determine the required cross-sectional area of each member

2. ?

3. Im not really sure what the problem is wanting. Any help would be appreciated, i work during my teachers office hours and have a test friday. thanks

#### Attached Files:

• ###### hw.jpg
File size:
6.4 KB
Views:
62
2. Sep 17, 2009

### CFDFEAGURU

The problem is asking you to find the cross-sectional area based on an allowable stress of 150 MPa in tension and 75 MPa in compression.

What you need to do is to determine the force in each truss member and then determine if that member is in compression or tension. Once the force is known and knowing if the member is in tension or compression the cross-sectional area can be found from the simple formula for stress.

Stress = Force/Area

Thanks
Matt

3. Sep 17, 2009

### mustang1988

when you say truss member do i use the momentum to find it? And do the two rollers have x and y components or are they irrelivant?

Last edited: Sep 17, 2009
4. Sep 17, 2009

### CFDFEAGURU

No, this has nothing to do with momentum. Do you know what a free body diagram is?

Truss is the name of the structure. The truss is made up of members. Do you follow?

Thanks
Matt

5. Sep 17, 2009

### mustang1988

yeah i know what a freebody diagram is i just dont understand what members i am looking for the tension and compression in? And if the force is just the two forces listed?