- published: 29 May 2014
- views: 7003681
A number is a mathematical object used to count, measure, and label. The original examples are the natural numbers 1, 2, 3, and so forth. A notational symbol that represents a number is called a numeral. In addition to their use in counting and measuring, numerals are often used for labels (as with telephone numbers), for ordering (as with serial numbers), and for codes (as with ISBNs). In common usage, the term number may refer to a symbol, a word, or a mathematical abstraction.
In mathematics, the notion of number has been extended over the centuries to include 0, negative numbers, rational numbers such as and , real numbers such as and , complex numbers, which extend the real numbers by including , and sometimes additional objects. Calculations with numbers are done with arithmetical operations, the most familiar being addition, subtraction, multiplication, division, and exponentiation. Their study or usage is called arithmetic. The same term may also refer to number theory, the study of the properties of the natural numbers.
Thunder is the sound caused by lightning. Depending on the distance and nature of the lightning, thunder can range from a sharp, loud crack to a long, low rumble (brontide). The sudden increase in pressure and temperature from lightning produces rapid expansion of the air surrounding and within a bolt of lightning. In turn, this expansion of air creates a sonic shock wave, similar to a sonic boom, which produces the sound of thunder, often referred to as a clap, crack, or peal of thunder.
The cause of thunder has been the subject of centuries of speculation and scientific inquiry. The first recorded theory is attributed to the Greek philosopher Aristotle in the fourth century BC, and an early speculation was that it was caused by the collision of clouds. Subsequently, numerous other theories were proposed. By the mid-19th century, the accepted theory was that lightning produced a vacuum.
In the 20th century a consensus evolved that thunder must begin with a shock wave in the air due to the sudden thermal expansion of the plasma in the lightning channel. The temperature inside the lightning channel, measured by spectral analysis, varies during its 50 μs existence, rising sharply from an initial temperature of about 20,000 K to about 30,000 K, then dropping away gradually to about 10,000 K. The average is about 20,400 K (20,100 °C; 36,300 °F). This heating causes a rapid outward expansion, impacting the surrounding cooler air at a speed faster than sound would otherwise travel. The resultant outward-moving pulse is a shock wave, similar in principle to the shock wave formed by an explosion, or at the front of a supersonic aircraft.
Stick it up, mister!
Can you hear what I'm saying now, yeah
Get your hands in the air, sir!
And you will get no hurt, mister, no no no
I said yeah (I said yeah)
Listen what they say (listen what they say)
Can you hear me say, yeah? (yeah yeah)
Listen what they say (listen what they say)
Do you believe I would take such a thing with me
And give it to a police man?
I wouldn't do that, oh no (ooh, ooh)
I wouldn't do that (ooh, ooh)
And if I do that, I would say "Sir,
come on and put the charge on me"
I wouldn't do that (ooh, ooh)
I wouldn't do that (ooh, ooh)
I'm not a fool to hurt myself
So I was innocent of what they done to me
They were wrong (ooh, ooh), oh yeah
They were wrong (ooh, ooh)
You give it to me one time (huh)
You give it to me two times (huh-huh)
You give it to me three times (huh-huh-huh)
You give it to me four times (huh-huh-huh-huh)
54-46 was my number, was my number, man
Right now, someone else has that number
54-46 was my number, well
Right now, someone else has that number
And I said yeah (I said yeah)
Listen what they say (listen what they say)
Can you hear me say, yeah? (yeah yeah)
Listen what they say (listen what they say)
Oh, work could not control me now
Oh, no bars could not hold me now
They hold I down and they lock-a you way
They try to keep I for a year and a day
But through the powers of the Most High God
Got to turn me lose, I say
54-46 was my number, was my number, man
Right now, someone else has that number, well
54-46 was my number, was my number, man