Science- Forces acting on structures Flashcards
Memorize
What is a structure?
A structure is something that holds or supports a load.
What two types of forces act on structures?
The two types of forces that act on structures are internal and external forces.
What are internal forces?
Internal forces are a part of the structure, such as a roof pushing down on four walls.
What are external forces?
External forces are not a part of the structure, such as snow on a roof.
What are two types of loads?
The two types of loads are live loads and dead loads.
What are live loads?
Live loads are temparory loads in a structure; not permanent.
What are dead loads?
Dead loads are permanent loads in the structure; not temporary.
What is a force?
A force is something that can make an object change speed, shape, or direction.
What are the two basic forces?
The two basic forces are pushing and pulling.
What are examples of pushing? Can pushing do all three things, which means it can change shape, direction and speed?
An example of pushing could be pushing a shopping cart. Pushing can make an object change it’s speed, shape, or direction.
What are examples of pulling? Can pulling change all three things? (Speed, shape, and direction.)
An example of pulling could be pulling open a door. Pulling can change an object’s speed, shape, or direction.
What is gravity?
Gravity is a force that pulls objects down towards earth.
What are the four types of internal forces?
Compression, Tension, Torsion and Bending
What is compression?
Compression is a pushing force that squeezes a material.
What is tension?
Tension is a pulling force that stretches a material.
What is torsion?
Torsion is a force that twists or turns a material.
What is bending?
Bending is a force that makes a straight material curved.
What are the 3 strongest shapes?
Rectangles, Arches and Triangles.
How can a rectangle be weakened? How did builders fix that?
Rectangles can be weakened when a force acts on one of it’s vertical sides. Rectangles can be made stronger with a support piece called a brace.
How can an arch be weakened? How can it be fixed?
Arches can be weakened when a force acts atop it. Arches can be made stronger with support pieces called buttresses.
How can a triangle be weakened?
Triangles can be weakened when a force acts on one of it’s vertical sides, causing it to bend.
What are the 4 types of bridges?
The 4 types of bridges are arch, beam, truss, and suspension bridges.
Describe an arch bridge. (In jot notes).
- Compression and tension is formed when a force acts atop it
- Stretches when a force acts atop it
- The material on the sides acts as buttresses
Describe a beam bridge. (In jot notes).
- Has one horizontal beam supported/held by two piers
- Bends when a load acts atop it
Describe a truss bridge. (In jot notes).
- Built with triangles made out of steel bars
Describe a suspension bridge. (In jot notes).
- Has one main cable that is held up by tall towers
- Main cable supports small cables
- Small cables support roadway
- These cables are called “suspenders”
