“Newton second”的意思、由来-开放百科全书

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Newton second

释义

Definition
Examples
See also
References

{{Infobox unit
| bgcolor =
| name = newton second
| image =
| caption = For two objects moving with the same velocity (v), the object with the greater mass (m) will have the greater momentum (p).
| standard = SI derived unit
| quantity = Impulse and momentum
| symbol = N s
| symbol2 =
| namedafter = Isaac Newton
| extralabel = In SI base units:
| extradata = kg ⋅ m/s
| units1 =
| inunits1 =
}}

The newton second (also newton-second, symbol N s or N·s)^[1] is the derived SI unit of impulse. It is dimensionally equivalent to the momentum unit kilogram metre per second (kg·m/s). One newton second corresponds to a one-newton force applied for one second.

It can be used to identify the resultant velocity of a mass if a force accelerates the mass for a specific time interval.

Definition

Momentum is given by the formula:

p is the momentum in newton second (N s) or "kilogram meters per second" (kg·m/s)
m is the mass in kilogram
v is the velocity in meters per second (m/s)

N s = N s= kg m/s

Examples

This table gives the magnitudes of some momenta for various masses and speeds.

Mass (kg)	Speed (m/s)	Momentum newton seconds	Explanation
0.42	2.4	1	A 420 gram football (FIFA specified weight for outdoor size 5) kicked to a speed of 8.6 km/h.
0.42	38	16	The momentum of the famous football kick of the Brazilian player Roberto Carlos in the match against France in 1997. The football had a speed of 137 km/h, making it one of the hardest kicks measured.
1,500	16.7	25,050	A regular small car weighing 1.5 tons crashing at 60 km/h
2,600	16.7	43,420	An SUV weighing 2.6 t (2.6 Mg) crashing at 60 km/h
6	1	6	The total impulse of a class C model rocket engine, which can be found in amateur fireworks.
10	2	20	The total impulse of a class D model rocket engine, which also can be found in amateur fireworks.
2,030,000	8050	1.63x10¹⁰	Space Shuttle launched from earth to orbit
45,702	10834	4.95x10⁸	Apollo 11 launched from earth to orbit
0.0075	350	2.6	9x19 mm 7.5 gram pistol round launched at 350 m/s
0.004	945	3.8	5.56 mm (0.223) 4 gram rifle round launched at 945 m/s
0.05	860	43	12.7x99 mm (0.50 BMG) 50 gram rifle round launched at 860 m/s

References

1. ^{{SIbrochure8th}}

3 : Classical mechanics|SI derived units|Units of measurement

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Definition

Examples

See also

References