The fossil record of animals goes back about 600 million years to the Ediacaran period, or somewhat earlier. During the whole of this long time, animals have been constantly evolving, so that the animals alive on Earth today are very different from those on the edges of the sea-floor in the Ediacaran. The study of ancient life is called palaeontology.
In scientific usage, humans are animals. But in everyday use, humans are often not regarded as animals.
Acceleration
Acceleration is a measure of how fast velocity changes. Acceleration is the change of velocity divided by the change of time. Acceleration is a vector, and therefore includes both a size and a direction. Acceleration is also a change in speed and direction, there is:
Speed (a scalar quantity) (uses no direction)
Velocity (a vector quantity) (uses a direction)
The measurement of how fast acceleration changes is called jerk.
Acceleration is the rate of change of the velocity of an object. Acceleration formula_1 can be found by using:
where
Sometimes the change in velocity formula_6 is written as Δformula_7. Sometimes the change in time formula_8 is written as Δt.
In difficult situations, the acceleration can be calculated using mathematics: in calculus, acceleration is the derivative of the velocity (with respect to time), formula_9.
Acceleration has its own units of measurement. For example, if velocity is measured in meters per second, and if time is measured in seconds, then acceleration is measured in meters per second squared (m/s).
Acceleration can be positive or negative. When the acceleration is negative (but the velocity does not change direction), it is sometimes called deceleration. For example, when a car brakes it decelerates. Physicists usually only use the word "acceleration".
Newton's laws of motion are rules for how things move. These rules are called "laws of motion". Isaac Newton is the scientist who first wrote down the main laws of motion.
According to Newton's Second Law of Motion, the force something needs to accelerate an object depends on the object's mass (the amount of "stuff" the object is made from or how "heavy" it is).
The formula of Newton's Second Law of Motion is formula_10,
where formula_11 is the acceleration, formula_12 is the force, and formula_13 the mass.
This formula is very well-known, and it is very important in physics. Newton's Second Law of Motion, in short "Newton's Second Law", is often one of the first things that physics students learn.
Deceleration is negative or backwards acceleration. This means that something slows down instead of speeding up. For example, when a car brakes, it is decelerating.
Black pudding
Black pudding is an English name for zwarte pudding. It is food made by cooking down the blood of any mammal (usually pigs or cattle) with meat, fat or filler until it is thick enough to congeal (become firm or solid) when cooled.
In Great Britain, blood sausage is called "black pudding". The ingredients include pig's blood, suet, bread, barley and oatmeal. The most common kind of German "blutwurst" is made from fatty pork meat, beef blood and filler such as barley. Though already cooked and "ready to eat" it is usually served warm.
Other kinds of blood sausage include "boudin noir" (France), "boudin rouge" (Creole and Cajun) and "morcilla" (Spain).
A legend says that blood sausage was invented in a bet between two Bavarian butchers drunk on the alcoholic drink absinthe during the 14th century. Homer's "Odyssey" from Ancient Greece says that "As when a man besides a great fire has filled a sausage with fat and blood and turns it this way and that and is very eager to get it quickly roasted...".
Boot device
A boot device is used to start a computer. It is named after a boot which fits on the foot. The word bootstrap is also closely related, and means, to use something simpler to get something more complex to make itself work better. It comes from the English phrase "pull yourself up by your own bootstraps."
Before a computer can operate normally, it must have operating system instructions that tell it how to perform basic functions. A boot device loads the operating system into the memory of the computer.
Devices that can boot a computer are usually boot disks or boot drives (normally a hard drive or Solid State Drive, but can be a floppy disk, flash drive or a CD). Some network computers use "boot chips" that get the operating system over a network. Web phones also use such chips to identify the user to the mobile phone network. Boot card standards may let many users boot kiosk computers with full privacy and access to all application software they own. There are also boot boards or boot "add-in" cards that are more permanent than boot cards.
Some people refer to the boot device as just a boot and non-boot devices as data devices, although it is not the computer but the operating system that cares about the difference between these.
The boot in boot device is the same as booting (or starting up). This is short for bootstrapping, or to start with simple stuff and make complex stuff out of it.
Boot
A boot is a type of footwear that protects the foot and ankle. Boots are higher and larger than shoes and sandals. Some boots are high enough to protect the calves (lower part of the leg) as well. Some boots are held on with "bootstraps" or "bootlaces". Some also have spats or "gaiters" to keep water out. Most have a very strong "boot sole", the bottom part of a boot.
Bankruptcy
Bankruptcy is a legal process which happens when a person or an organization does not have enough money to pay all of its debts. Legally they are insolvent.
Where it is a person who cannot pay their debts, the person's creditors may ask the court to appoint a "trustee in bankruptcy". This is a professional accountant who is appointed by the court, to take control of the bankrupt person's assets. Some assets are protected by law, but the trustee in bankruptcy will sell off all of the other assets and use the money to pay as much of that person's debts as possible. After the process is complete the person is "discharged from bankruptcy", and the person is free from any further liability to pay those claims, but normally that person will be limited in their ability to borrow money again because their credit rating will be damaged.
Where it is an organisation which cannot pay its debts, the creditors may ask the court to appoint a "liquidator". The liquidator does a very similar job to the trustee in bankruptcy except that there are no assets which are protected so the liquidator can sell everything. Once all of the assets of the organisation have been sold, the organisation is then "dissolved" and no longer exists. Organisations do not get discharged from bankruptcy in the same way that a living person does.
People often confuse the terms bankruptcy and insolvency, and sometimes they use one word when they really mean the other. Insolvency usually just means that a someone does not have enough money to pay their debts or (sometimes) that the total amount of their debts is worth more than the total amount of their assets. Bankruptcy is a formal legal process in front of the courts. Although the two terms are connected, just because a person is insolvent does not necessarily mean that they will go into bankruptcy.
Many countries have alternatives to bankruptcy to try and allow people and businesses to try and avoid the bankruptcy process.
In various countries, individual people can try and reach "individual voluntary arrangements" (or IVAs) with their creditors. This means that the creditors agree to take less money to discharge their debts. There are similar processes for companies and other organisations, and they go by various different names in different countries, but in many countries they are called "schemes of arrangement".