Newton second
Newton-second | |
---|---|
General information | |
Unit system | SI derived unit |
Unit of | Impulse and momentum |
Symbol | N⋅s or N s |
Named after | Isaac Newton |
In SI base units: | kg⋅m/s |
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:
- is the momentum in newton-seconds (N⋅s) or "kilogram-metres per second" (kg⋅m/s)
- is the mass in kilograms (kg)
- is the velocity in metres per second (m/s)
Examples
This table gives the magnitudes of some momenta for various masses and speeds.
Mass (kg) |
Speed (m/s) |
Momentum (N⋅s) |
Explanation |
---|---|---|---|
0.42 | 2.4 | 1 | A 420-gram (15 oz) football (FIFA specified weight for outdoor size 5) kicked to a speed of 8.6 km/h (5.3 mph). |
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 (85 mph), making it one of the hardest kicks measured. |
1300 | 10 | 13000 | A four-door car weighing 1300 kg (2900 lb) crashing at 36 km/h (22 mph). |
2000 | 10 | 20000 | A mid-size SUV weighing 2000 kg (4400 lb) crashing at 36 km/h (22 mph). |
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. |
2030000 | 8050 | 1.63×10^{10} | Space Shuttle launched from earth to orbit |
45702 | 10834 | 4.95×10^{8} | Apollo 11 launched from earth to orbit |
0.0075 | 350 | 2.6 | A 7.5-gram (0.26 oz) handgun bullet (e.g. 9mm Parabellum) fired at 350 m/s (1100 ft/s). |
0.004 | 945 | 3.8 | A 4-gram (0.14 oz) assault rifle bullet (e.g. 5.56×45mm NATO) fired at 945 m/s (3100 ft/s). |
0.05 | 860 | 43 | A 50-gram (1.8 oz) machine gun bullet (e.g. .50 BMG) fired at 860 m/s (2800 ft/s). |
See also
- Power factor
- Newton-metre, the derived SI unit of torque
- Orders of magnitude (momentum), for examples of momenta
References
- ^ International Bureau of Weights and Measures (2006), The International System of Units (SI) (PDF) (8th ed.), ISBN 92-822-2213-6, archived (PDF) from the original on 2017-08-14
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