TRANSFORMATION OF MOTION

The linear motion can be undirectional or reciprocating.

- Rotary-linear transformation.
· Wheel.
If the wheels isn't enough friction, the wheels can slide out of control.
A wheel moves forward a distance that is equal to its circumference.

· Rack and pinion mechanism.
A rack and pinion mechanism has two parts.The rack is a bar with many teeth and the pinion is a gear with teeth that interlock with the rack. When the pinion rotates, the rack moves in a linear direction. If the mechanism is reversible, the pinion also rotates when the rack moves.
The mechanism transforms rotery motion into linear motion.

· Nut and bolt mechanism.
A nut and bolt mechanism transforms rotary motion into linear motion. It has two parts: a bolt or shaft with a spiral groove and a nut that turns around it.

· Winch and crank mechanism.
A winch is a cylinder that rotates around a horizontal axis. Then we turn the crank to rotate the winch.
The increase in force is proportional to the ratio between the radius of the crank and the radius of the winch

- Reciprocating rotary-linear transformation.
For example, the pedal mechanism of a bycicle transforms the reciprocating movements of our legs into continuous rotary motion.

· Crank and rod mechanism.
The piston moves a rod forwards and backwards. We find cranks and roda in internal combustion engines, as well as windscreen wiper mechanisms.

· Crankshaft mechanism.
We can connect multiple rods to one shaft. The rods are connected to cranks, and the cranks are connected to the crankshaft.

· Cam mechanism.
A cam is an irregularly shaped device that rotates on a shaft. When the cam rotates, it pushes a special bar called a follower. The follower can move other parts or it can turn a switch on and off. We can put multiple cams on one shaft, called a camshaft.
Some cams are circular, but with an axis of rotation that is off-centre. These are called eccentric cams because they rotate in an irregular or eccentric way.

ROTARY TRANSMISSION

Rotary transmission systems put two rotating elements into contact. These mechanisms have two purposes:
· Transfering rotary force from an input location to another.
· Changing the rotary speed by using rotating elements of different sizes.

We can perform these functions with various mechanisms:
· Friction wheels.
· Pulleys with belts.
· Interlocking gears.
· Sprockets with chains.

Friction wheels and pulleys are used in toys and other devices, such as industrial rollers or conveyor belt systems. Gears are in clocks. Sprockets and chains are common in home appliances.

- Changes in speed.
If we want to increase the speed of a rotary system, we must transmit motion from a large (input) element to a smaller (output) element.

When we increase the speed we also decrease the rotary force. The rotary force will also remain constant.
· Increasing speed system: the input speed is lower than the output speed.
· Constant speed system: the input speed and the output speed are equal.
· Decreasing speed system: the input speed is higher than the output speed.

The relationship between the speeds of the two wheels is inversily proportional to their sizes.

- Belt drives and gear trains.
A belt drive is a system of pulleys connected by belts. Each belt connects a pair of pulleys, so they turn together.

To calculate the ratio of transmission between the first wheel and the last wheel of a belt drive, we must multiply the ratios of transmission of the first pair of wheels and the second pair of wheels.

- Changes in direction and rotation.
We can use various systems to change the direction of rotation or the axis of rotation in a belt drive. We use different types of gears when two axes are parallel, perpendicular or crossed.

In some gear mechanisms, several cogs or teeth interlock at the same time. These mechanisms are more precise and they transmit more rotary force.

- Worm drive.
A worm drive reduces the speed of a rotary system very effectively. A worm drive has two parts: a worm shaft and a worm gear.

When the worm shaft makes one rotation, the worm gear moves forward one tooth for every groove on the shaft.

We use worm drives for tuning the strings of a guitar, for elevator mechanisms and for speed reducing systems.

LINEAR TRANSMISSION OF MOTION

The linear transmission mechanisms, use linear motion input to produce linear motion output.
  
- Levers.
A lever is a rigid bar that turns around a point called a fulcrum. Each force produces a specific torque, which is the force multiplied by its distance from the fulcrum.
Torque = Force x Distance
We say the lever is in equilibrium when the opposite end of a lever are equal.
Law of the lever: F x d = R x r
F: the force; d: the distance from the fulcrum; R: the resistance; r: distance from the fulcrum.

·Classes of levers.
Class 1: the force applied is increased or decreased. The fulcrum is between the force and the resistance.
Class 2: the force applied is always increased. The resistance is between the fulcrum and the force.
Class 3: the force applied is always decreased. The force is between the fulcrum and the resistance.

- Pulleys and compound pulley systems.
In a system of pulleys, the equilibrium between the forces depends on the path that the rope follows.

· Pulleys.
A pulley is a wheel that rotates around an axis and has a groove. We can divide pulleys into two basic types:
Fixed pulley: the forces are equal because the rope moves the same distance on both sides.
Movable pulley: the rope follows a double path around the pulleys. We need half the force to lift the same weight as with a fixed pulley.

· Compound pulley systems.
A compound pulley system is a combination of fixed and movable pulleys. It is also called a block and tackle system. The more pulleys there are, the less force we need to lift the load. We can combine the pulleys in various ways:
Vertical system: F = R/2 x n (n is the number of pulleys)
Horizontal system: F = R/2 x n
Exponential system: F = R/2 (2 elevated to the number of pulleys n)

MECHANISMS

For example, the parts of a bicycle are mechanisms.

A mechanisms transmit and transform force and motion. Require an input force and motion.

Mechanisms transmit motion and force to receptors that finally perform the work, this is the output force and motion.

- The parts of a mechanism.

In the case of a bicycle, your legs provide the force and motion, the pedals transmits the input motion and transmit to the back wheel (the output receptor).

Mechanisms transmit and transform force and motion from an input source to an output receptor.

- Classification of mechanisms.
Classification by the work that they do.
· Transmission of motion.
Linear transmission: lever, pulley, block and tackle.
Rotary transmission: friction wheels, belt drive, gears, chain drive.

· Transformation of motion.
Rotary-linear: wheel, rack and pinion, nut and bolt, crank.
Reciprocating rotary-linear: crank and rod, crankshaft, cam, eccentric cam.

· Motion control.
Direction control: ratchet, freewheel.
Speed reduction: brake.

· Energy accumulation.
Absorption / Dissipation: spring.

· Connection.

Linkage: clutch.
Support: plain bearing.

CREATING INFORMATION

The most popular tools for creating and distributing information on the Internet are web pages, blogs and wikis.

- Web pages.
The first step is to plan the design and content of everything.
The content must be interesting and visually appealing in order to attract the maximum number of visits. The steps that you must follow are:
1- Register a domain.
2- Sign up with a host server.
3- Design and create your web page.
4- Upload your page on the server.
5- Update your page regularly.

Domain names.
To register a domain you must choose a name.

Host servers.
Domain registration services may also provide hosting, and web page design companies often include both registration and hosting.

Designing a web page.
You need some basic knowledge of design, to insert images and change colours, will make your web page more attractive with this examples:

· Title.
The title indicate the topic of your web page and appears in the banner section of a web browser.

· Colour combinations.
You can combine colours for call the attention.

· A balanced layout.
The distribution are very important, we can use tables to structure the information in columns and rows.

·Hyperlinks.
Hyperlinks can be added to images or texts. There are two types:
· External links take us to other websites related to the topic.
· Internal links take us to a different part of the same website.

· Visual impact.
· The combination of  and .
· We can add animated gifs. We can also use dynamic text formats.

· Comments from users.
You shouldn't give any personal information on the Internet.

· Page order.
If you have created various pages, you can join them together with internal links.
· Linear order: One page follows another.
· Hierarchical order: We can link to any other page that we like.

Creating your web page.

1. Direct programming requires knowledge of programming languages and tools.

· HTML (Hypertext Markup Language) is used for static web page design.

· CSS (Cascade Style Sheets) is used to create the structure of a document.

· PHP (Hypertext Preprocessor) is a language used to create dynamic web pages.

· MySQL is a database management system used for dynamic web pages.

2. Using a Content Management System (CMS): We can use CMS to create dynamic web pages. These systems have several advantages:
a) They are fast because they don't require direct programming.
b) Some are free.
c) Some CMS services offer a package that includes hosting and CMS installation.

There are also some disadvantages:
a) You cannot do anything you want.
b) CMS programs are complex and it takes a long time to learn how to use them.
c) You must have a server with enough storage space for the program.

The most popular services are Joomla!, Drupal and Wordpress.

3. Using a web development program: This type of programs translate your web page design into HTML language.
Some programs are more powerful because they have more functions.

4. Using the online hosting services that some pages offer: You select the elements of your web page from a menu with different options and add them to one of the many templates that are offered. The free versions have limitations:
a) They include advertising, which some people may find unattractive.
b)The web address may be rather long and difficult to remember.
Wix is one of the most popular.

Uploading a web page to a server.
You need to upload your CMS or your web page to the server.
You can use a FTP (File Transfer Protocol) programs to upload your web page to the server.

Completing and updating a web page.
The content is always up to date.

- Blogs
Weblogs or blogs are a special type of web page. There were originally used as online diaries for people to share their personal experiences. They are interesting because have other characteristics:
· The blog can be shared by various bloggers working together as a team.
· Can be include hyperlinks to photos, audio recordings or videos.
· We can use blogs to make daily reports.
· Businesses can use blogs to improve their customer service, by quickly responding to questions or complaints about their products.
Blogger, Wordpress and Tumblr are the most popular.

- Wikis.
A wiki is a collection of web pages that visitors can edit, modify or expand. Adding new content to a wiki page is quite easy:
1- Click on the Edit button.
2- Make changes to the existing content or write a new contribution.
3- Finally click on the Save button.

Wikipedia
Wikipedia is a universal encyclopedia with no restrictions on use, you can modify the content .

SHARING INFORMATION

Social networks as virtual environments for communication, interaction and the sharing of resources. They can be divided into two groups: horizontal and vertical.

- Horizontal social networks.
The users create communities. The most popular are:

· Facebook.
This application allows groups to publish public or private messages with text, links, news, photos and videos. Lets you know what people are doing at any paricular moment.

· Twitter.
In this application the users publish short text messages (tweets) with no more than 140 characters, which is called microblogging. The relationships between users are not always bidirectional.
People use hashtags to follow interesting events or topics.

· Google+.
This social network allows users to create groups to share information. They can share photos and form public or private communities.

- Vertical social networks.
The users form communities who have similar reasons for using the application. These reasons, which can be personal or professional, may include:

· Sharing professional information: The most popular network is LinkedIn.

· Sharing general information: People can create private groups to share information, for example with FriendFeed.

· Sharing photos: Instagram are one of the most popular.

· Sharing videos: YouTube among others.

· Live streaming: Live streaming is a technique for sharing very large audio and video files. For example Skype or Livestream.

· Other services related to other topics: For example related to books, Wattpad.

MANAGING INFORMATION

- Social bookmarking.
Social bookmarking is an Internet tool that let us organise, use and share information more efficiently, all of our content is stored in the cloud (an online storage system for files) so we can access it from any location in the world. Some of the most popular social bookmarking applications are:

· Delicious.
Is a service that let us save our favourite web pages and classifies them with a description and tags. We can share this information with other people.

· Diigo.
Is a multi-tool for knowledge management. We bookmark the pages that we visit and create a digital library in the cloud, with links, notes and images.

· Evernote.
We can collect information by capturing articles and images from the Internet. This application is used for finding specific details in the content that we have saved, and convenient for making presentations.
  
- Working in the cloud.
Some Internet services let us create, save and modify documents online, for example Google Drive, Dropbox and OneDrive. This services have two advantages:
· Access to our files from any location.
· The ability to share our files easily with other people.
We can use programs for word-processing, spreadsheets and presentations to storing and sharing information.
Services as Flickr and Picassa, let us upload and edit photos in the cloud. 

FINDING INFORMATION

The sources of online information are web pages and news feeds (RSS).

- Web pages.
A web page is a collection of documents that can include text, audio, video, images and hypertext links to other web pages. A browser is a program that locates a web page, for example Chrome, Safari or Firefox.
When we want find an specific information we use a search engine, is a web page with a database of information about other web pages and their content. 

- News feeds: Really Simple Syndication (RSS).
Really Simple Syndication (RSS) is a subscription service that provides users with frequent updates from media websites or other sources of information.
RSS news feeds are convenient and time-saving. Since subscribers receive the news automatically, they don't have to visit so many websites because people can subscribe in two ways:
·From the web page.
·Through a news aggregator program, for example Feedly.

WEB 1.0, WEB 2.0, WEB 3.0

When we talk about Web 1.0, 2.0 or 3.0 we aren't only talking about the Internet, we're also talking about the way that users participate in activities online.

- WEB 1.0 or the read-only web.
The information on the Internet was only for reading. It was a network of documents but people couldn't interact with the content.

- WEB 2.0 or the social network.
The information became bidirectional and not only receive information, but also create and share it.

- WEB 3.0 or the semantic web.
The new technologies allowed the integration of data and the web so that programs could manage the information that they received.