Browse Definitions :


The newton-second (N · s) is the standard unit of impulse. Reduced to base units in the International System of Units ( SI ), a newton-second is the equivalent of a kilogram-meter per second (kg · m/s or kg · m · s -1 ). In terms of literal units, impulse is equivalent to momentum, although there is a conceptual difference between the two phenomena.

As an example of impulse and its relationship with momentum, consider a rocket ship coasting through space at a speed of 10,000 (10 4 ) m/s. Suppose the ship's forward thrusters are fired for a period of 10 s, and they produce a total force of 100,000 (10 5 ) N. The impulse I generated is equal to the product of the force F and the time t :

I = Ft

= 10 5 kg · m/s 2 · x 10 s = 10 6 kg · m/s

A rule of Newtonian physics states that the impulse imparted to an object is equal to the change in momentum for that object, provided no other forces or effects are involved. Therefore, by firing the rockets so an impulse of 10 6 kg · m/s is produced in the forward direction, the forward momentum of the vessel is increased by 10 6 kg · m/s. If the retro rockets are fired so the impulse is contrary to the direction of the ship's motion, then the forward momentum of the ship will be reduced by 10 6 kg · m/s.

The equivalence of impulse and change in momentum holds regardless of the mass of the object to which the impulse is applied.

Also see newton and Table of Physical Units .

This was last updated in March 2011
  • pure risk

    Pure risk refers to risks that are beyond human control and result in a loss or no loss with no possibility of financial gain.

  • risk reporting

    Risk reporting is a method of identifying risks tied to or potentially impacting an organization's business processes.

  • chief risk officer (CRO)

    The chief risk officer (CRO) is the corporate executive tasked with assessing and mitigating significant competitive, regulatory ...

  • encryption key

    In cryptography, an encryption key is a variable value that is applied using an algorithm to a string or block of unencrypted ...

  • payload (computing)

    In computing, a payload is the carrying capacity of a packet or other transmission data unit.

  • script kiddie

    Script kiddie is a derogative term that computer hackers coined to refer to immature, but often just as dangerous, exploiters of ...

  • What is risk mitigation?

    Risk mitigation is a strategy to prepare for and lessen the effects of threats faced by a business.

  • fault-tolerant

    Fault-tolerant technology is a capability of a computer system, electronic system or network to deliver uninterrupted service, ...

  • synchronous replication

    Synchronous replication is the process of copying data over a storage area network, local area network or wide area network so ...

  • cloud NAS (cloud network attached storage)

    Cloud NAS (network attached storage) is remote storage that is accessed over the internet as if it is local.

  • Terabyte (TB)

    A terabyte (TB) is a unit of digital data that is equal to about 1 trillion bytes.

  • object storage

    Object storage, also called object-based storage, is an approach to addressing and manipulating data storage as discrete units, ...