Time is the expression of eternal movement, continuity and changing order of matter, including two concepts: time and time period. Time is a parameter used by human beings to describe the process of material movement or the occurrence of events. The determination of time depends on the law of material circulation that is not affected by the outside world. The time measurement system based on the earth's rotation is called universal time system. Time measurement of time, day, month, year and century belongs to the calendar category in astronomy. Time is one of the seven basic physical quantities in physics, and the symbol is T. In the International System of Units (SI), the basic unit of time is seconds, and the symbol is S.

Second, the point (mathematical concept)

The unit describing the angle of a circle, with the symbol.

Divide a circle 360 into equal parts, and each part is called a degree.

Divide a degree into 60 equal parts, and each equal part is called one minute.

Divide a minute into 60 equal parts, and each equal part is called a second.

Three seconds

(1) Angle unit

Seconds is the basic unit of angle in the international system of units. One second is equal to 1/60 minutes. Seconds is the basic unit of the angle at which an angle (a geometric object composed of two rays with a common endpoint) opens, and it is an extremely tiny angular unit, which is 1/3600 degrees.

The Unicode code corresponding to the symbol of seconds is: 2033[ 1] (hexadecimal), which is displayed as ".".

convert

One second = 1/60 minutes.

One second = 1/3600 degrees.

1″= 1/60′

1″= 1/3600

60″= 1′= 1/60

3600″=60′= 1

(2) Time unit

Seconds is the basic unit of time in the international system of units.

The prefix of the international system of units is often combined with seconds to make a finer division, such as ms (millisecond, thousandth of a second), μs (microsecond, millionth of a second) and ns (nanosecond, billionth of a second). Although the international unit prefix system can also be used to extend time, such as Ks (thousands of seconds), Ms (millions of seconds) and Gs (billions of seconds), it is rarely used in this way, and people are still used to using 60-decimal minutes, hours and 24-decimal days as the extension of seconds.

Time relation

1 international second is equivalent to:

1/60 points

1/3600 hours

1/86400 days (time unit of the International Astronomical Union)

1/3 1,557,600? Julian year (time unit of the International Astronomical Union)

Second conversion

1s = 10 3 ms (milliseconds) = 10 6 μ s (microseconds) = 10 9 ns (nanoseconds) =10/2ps (picoseconds) = 65438.