Particle displacement

Particle displacement or displacement amplitude is a measurement of distance of the movement of a particle from its equilibrium position in a medium as it transmits a sound wave. The SI unit of particle displacement is the metre (m). In most cases this is a longitudinal wave of pressure (such as sound), but it can also be a transverse wave, such as the vibration of a taut string. In the case of a sound wave travelling through air, the particle displacement is evident in the oscillations of air molecules with, and against, the direction in which the sound wave is travelling.

A particle of the medium undergoes displacement according to the particle velocity of the sound wave traveling through the medium, while the sound wave itself moves at the speed of sound, equal to 343 m/s in air at 20 °C.

Mathematical definition

Particle displacement, denoted δ, is given by

where v is the particle velocity.

Progressive sine waves

The particle displacement of a progressive sine wave is given by

Adobe After Effects

Adobe After Effects is a digital visual effects, motion graphics, and compositing application developed by Adobe Systems and used in the post-production process of filmmaking and television production. Among other things, After Effects can be used for keying, tracking, rotoscoping, compositing and animation. It also functions as a very basic non-linear editor, audio editor and media transcoder.

Description

Adobe After Effects is software primarily used for creating motion graphics and visual effects. It allows users to animate, edit, and compose media in 2D or 3D space with many different built-in tools and third party plug-ins which can be downloaded from the Internet depending on what type of plug in the user is looking for. It also provides individual attention to variables like parallax and also user adjustable angles of observation.

Adobe After Effects is a layer-oriented program. Each individual media object like video clips, still images, audio clips, etc. runs on its own. In contrast, other Non-Linear Editing Systems use a system where individual media objects can occupy the same track as long as they do not overlap at the same time. This track-oriented system is more suitable for editing and can keep project files more simple. The layer oriented system that Adobe After Effects has is suitable for extensive video effects work and also key framing. Other compositing packages, especially the ones that employ tree or node workflows, such as Nuke and Fusion, are better suited to managing complex interconnected data flow within a composite. Adobe After Effects is capable of countering the problem somewhat by selectively hiding layers or by grouping them into pre-compositions.

Khan Academy

Khan Academy is a non-profit educational organization created in 2006 by educator Salman Khan with the aim of providing a free, world-class education for anyone, anywhere. The organization produces short lectures in the form of YouTube videos. In addition to micro lectures, the organization's website features practice exercises and tools for educators. All resources are available for free to anyone around the world. The main language of the website is English, but the content is also available in other languages.

History

The founder of the organization, Salman Khan, was born in New Orleans, Louisiana, United States to immigrant parents from Bangladesh and India. After earning three degrees from the Massachusetts Institute of Technology (a BS in mathematics, a BS in electrical engineering and computer science, and an MEng in electrical engineering and computer science), he pursued an MBA from Harvard Business School.

In late 2004, Khan began tutoring his cousin Nadia who needed help with math using Yahoo!'s Doodle notepad.When other relatives and friends sought similar help, he decided that it would be more practical to distribute the tutorials on YouTube. The videos' popularity and the testimonials of appreciative students prompted Khan to quit his job in finance as a hedge fund analyst at Connective Capital Management in 2009, and focus on the tutorials (then released under the moniker "Khan Academy") full-time.

Displacement

Displacement may refer to:

Physical sciences

Physics