Science- Forces acting on structures

Question 1

What is a structure?

Answer 1

A structure is something that holds or supports a load.

Question 2

What two types of forces act on structures?

Answer 2

The two types of forces that act on structures are internal and external forces.

Question 3

What are internal forces?

Answer 3

Internal forces are a part of the structure, such as a roof pushing down on four walls.

Question 4

What are external forces?

Answer 4

External forces are not a part of the structure, such as snow on a roof.

Question 5

What are two types of loads?

Answer 5

The two types of loads are live loads and dead loads.

Question 6

What are live loads?

Answer 6

Live loads are temparory loads in a structure; not permanent.

Question 7

What are dead loads?

Answer 7

Dead loads are permanent loads in the structure; not temporary.

Question 8

What is a force?

Answer 8

A force is something that can make an object change speed, shape, or direction.

Question 9

What are the two basic forces?

Answer 9

The two basic forces are pushing and pulling.

Question 10

What are examples of pushing? Can pushing do all three things, which means it can change shape, direction and speed?

Answer 10

An example of pushing could be pushing a shopping cart. Pushing can make an object change it’s speed, shape, or direction.

Question 11

What are examples of pulling? Can pulling change all three things? (Speed, shape, and direction.)

Answer 11

An example of pulling could be pulling open a door. Pulling can change an object’s speed, shape, or direction.

Question 12

What is gravity?

Answer 12

Gravity is a force that pulls objects down towards earth.

Question 13

What are the four types of internal forces?

Answer 13

Compression, Tension, Torsion and Bending

Question 14

What is compression?

Answer 14

Compression is a pushing force that squeezes a material.

Question 15

What is tension?

Answer 15

Tension is a pulling force that stretches a material.

Question 16

What is torsion?

Answer 16

Torsion is a force that twists or turns a material.

Question 17

What is bending?

Answer 17

Bending is a force that makes a straight material curved.

Question 18

What are the 3 strongest shapes?

Answer 18

Rectangles, Arches and Triangles.

Question 19

How can a rectangle be weakened? How did builders fix that?

Answer 19

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.

Question 20

How can an arch be weakened? How can it be fixed?

Answer 20

Arches can be weakened when a force acts atop it. Arches can be made stronger with support pieces called buttresses.

Question 21

How can a triangle be weakened?

Answer 21

Triangles can be weakened when a force acts on one of it’s vertical sides, causing it to bend.

Question 22

What are the 4 types of bridges?

Answer 22

The 4 types of bridges are arch, beam, truss, and suspension bridges.

Question 23

Describe an arch bridge. (In jot notes).

Answer 23

• 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

Question 24

Describe a beam bridge. (In jot notes).

Answer 24

• Has one horizontal beam supported/held by two piers
• Bends when a load acts atop it

Question 25

Describe a truss bridge. (In jot notes).

Answer 25

• Built with triangles made out of steel bars

Question 26

Describe a suspension bridge. (In jot notes).

Answer 26

• 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”