Newton-second

The newton-second (also newton second; symbol: N⋅s or N s) is the unit of impulse in the International System of Units (SI). 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.

:<math>\vec F \cdot t = \Delta m \vec v</math>

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:

:<math>\mathbf{p} = m \mathbf{v},</math>

<math>\mathbf{p}</math> is the momentum in newton-seconds (N⋅s) or "kilogram-metres per second" (kg⋅m/s)
<math>m</math> is the mass in kilograms (kg)
<math>\mathbf{v}</math> is the velocity in metres per second (m/s)

Examples

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

{| class="sortable wikitable"

! Mass <br/>(kg)

! Speed <br/>(m/s)

! Momentum <br/>(N⋅s)

! Explanation

| 0.42

| 2.4

| 1

| A football (FIFA specified weight for outdoor size 5) kicked to a speed of .

| 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 , making it one of the hardest kicks measured.

| 10

| A four-door car weighing crashing at .

| 10

| A mid-size SUV weighing crashing at .

| 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.

| Space Shuttle launched from Earth to orbit

| Apollo 11 launched from Earth to orbit

| 0.0075

| 350

| 2.6

| A handgun bullet (e.g. 9mm Parabellum) fired at .

| 0.004

| 945

| 3.8

| A rifle bullet (e.g. 5.56×45mm NATO) fired at .

| 0.05

| 860

| 43

| A anti-material bullet (e.g. .50 BMG) fired at .

Definition

Examples

See also

References