Method of Sections
Moment of Inertia
Shear Moment Diagrams
100
What is the first step of method of sections?
Find the reaction forces
100
What is the moment of inertia of a rectangle?
b*h3/12
100
The moment diagram is the _____ of the moment diagram diagram
Derivative
200
Which side of the split truss do you work on?
Trick question! Either one.
200
What is parellel axis theorum?
Describing the moment of inertia of an object whose centroid does not pass through the origin. Area*distance^2
200
The shear diagram is the ____ of the load diagram
Integral
300
Does the cut line need to be continuous?
Yes. Two distinct shapes need to be created. This can only be done with a continuous line.
300
How do you calculate Jo (polar moment of inertia)
Ix+Iy
300
What indicator can you use that suggests you have MOST LIKELY done the problem correctly?
Both the shear and moment diagrams close
400
Does the splitting line need to be perfectly straight? Why?
No! It can curve. The internal forces are assumed to be constant within each member, so the location of the cut does not matter.
400
What does moment of inertia describe conceptually?
An object's resistance to change in velocity
400
The shear diagram crossing the x-axis corresponds to what behavior of the moment diagram?
A minimum or maximum
500
Why might Zsuzsa prefer this method to method of joints?
Mistakes stack, including rounding errors when method of joints is used. The same is not true for method of sections.
500
Shear walls resist wind loads. Which direction is the wind travelling in based on the orientation of these shear walls? Explain why to get full points.
Into/out of the page. Think about which side of a ruler is harder to bend.
500
If you wanted to use calculus to find the shear diagram, you would get an indefinite integral. What would you use as an initial condition to create a definite integral?
The reaction forces with their location
600
What strategy can you use to reduce the number of components you need to deal with?
(two acceptable answers, meaning double points if you can get both!)
1. Select the pivot point in line with the forces you want to cancel out
2. Find the point along the line of action at which the force you want to find will be perpendicular to the pivot
600
Medicine ball, dumbbell, empty barbell, plated barbell
600
If an isolated moment is on the loading diagram, describe the behavior on the shear and moment diagrams
Shear: ignore
Moment: a vertical line
700
What equations are used for method of sections?
sumFx
sumFy
sumM
700
What will win the race down a slope, disk, hollow ball, or solid ball?
Solid ball
700
A triangular distributed load is on the loading diagram. Describe how this impacts the calculation of the reaction forces and the shear diagram.
Reaction calculation: Treat it as a point load with magnitude equal to area and location through the centroid.
Shear: treat as a distributed load again. It will create a parabolic shape