# Forces and Structures

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Forces and Structures

## 3. Types of structures

### 3.1. Frame

3.1.1. There are different types of structures such as a frame structure. This only consists of a frame or more than one frame in it such as a crane or the Eiffel Tower!

### 3.2. Shell

3.2.1. Another type of structure could be shell structure. This structure consists of a hollow inside commonly used to put things in such as a hat of some sort, or a light bulb.

### 3.3. Solid

3.3.1. A solid structure is a structure that is solid all the way through the structure, this can be an advantage for tough structures but not for people who like light structures. Two examples are an ice sculpture and jello.

### 3.4. Combination

3.4.1. A combination is a structure with all these features above. This would make the structure very sturdy and it is a commonly used structure. two examples are a house which has a frame, a solid wall, hollow poles and the hollow house itself; and a human, we have solid bones, a hollow nose (or as adults like to say a hollow head) and our skeleton is a frame.

## 4. External Forces

### 4.1. Point of application

4.1.1. This is the point where you apply the force that has been needed on the object such as when you push a box at the top, or when you kick a ball in the middle or the side.

### 4.2. Direction

4.2.1. When you put force on a structure, there is always a direction you put the force on, a push or a pull. For example, you can pull on a tug-of-war string and you can push on a swing.

### 4.3. Plane of application

4.3.1. This is the angle that you put force on the object such as putting a wrecking ball at a 180 degree angle on a wall creating more force; or, putting a 45 degree angle on a volleyball against your hands.

### 4.4. Magnitude

4.4.1. When you put force on an object, you always want to make sure how much force you put on it. An example would be that you would put a heavy magnitude on weights so you would be able to lift it; or, you would put a small magnitude on the buttons on a keyboard so you don't break the keyboard.

## 5. Form and Function

### 5.1. Form and function: Form is what the structure looks like. Function is what the structure does and how it works.

5.1.1. The form of a desk is that it has 4 legs and a hollow inside.

5.1.1.1. The form of a chair is that it has 4 legs and a strong seat that can support your weight.

5.1.2. The function of a desk is that you can put things in the hollow inside and you can also put things on top of it.

5.1.2.1. The function of a chair is that you can sit on it and it can support your weight.

5.1.2.1.1. The form and function of Leaning Tower of Pisa.

## 6. Internal forces

### 6.1. Internal forces is the forces that can effect external forces. When you hit a ball from any where on it, it will push or pull it forward or sideways, that's internal forces, which can control where the thing or ball is going and where it's going to hit.

6.1.1. Shear

6.1.1.1. This is where you have two opposite forces working in opposite directions to bend the object until it possibly breaks. Two examples are the scissors's blades cutting a paper, or a a heavy object sitting on a branch on a tree.

6.1.2. Torsion

6.1.2.1. Torsion is where you use two opposite directions on an object to twist it; an example is a wet towel being twisted to take all the water out, or motorcycle handles.

6.1.3. Tension

6.1.3.1. Tension is where you use two of the same direction to make your object tense. This one force is a pull and an example would be stretching an elastic band or trying to pull your hair out of stress.

6.1.4. Compression

6.1.4.1. Compression is the force that is applied when you press something down or when something presses something down. This force is a push. An example of compression would be chomping down on food or sitting on a chair.

7.1.1. This is where you have a load which can support its own weight, this is excluding the weight of passengers and goods. two examples are a chair and the CN tower, these two structures can support their own weight, this is caused by the force of gravity.

7.2.1. This is the opposite of a dead load, it cannot support its own weight because of the force of gravity so it would need something else to. For example, an apple would have to sit on a desk because the apple cannot support its weight; the same thing happens with a person sitting on a chair.

7.3.1. This is a load very similar to a live load. A dynamic load can change or it can be applied with motion. An example would be the wind being applied to a tree, or a tornado to a house.

7.4.1. This consists of two components, the weight of the dead load also caused by the live load. For example, a bike has dead loads such as the frame, the tire and the whole bike itself. The live load would be the human riding it and it might be heavy or light, but the weight would vary because of gravity as well. Sometimes, there is no live load so the static load it just the weight of the bike itself. Another example would be the weight of the golden gate (a bridge) and the cars on it.