To install click the Add extension button. That's it.

The source code for the WIKI 2 extension is being checked by specialists of the Mozilla Foundation, Google, and Apple. You could also do it yourself at any point in time.

4,5
Kelly Slayton
Congratulations on this excellent venture… what a great idea!
Alexander Grigorievskiy
I use WIKI 2 every day and almost forgot how the original Wikipedia looks like.
What we do. Every page goes through several hundred of perfecting techniques; in live mode. Quite the same Wikipedia. Just better.
.
Leo
Newton
Brights
Milds

Impulse (physics)

From Wikipedia, the free encyclopedia

Impulse
A large force applied for a very short duration, such as a golf shot, is often described as the club giving the ball an impulse.
Common symbols
J, Imp
SI unitnewton-second (Ns)
Other units
kgm/s in SI base units, lbfs
Conserved?yes
Dimension

In classical mechanics, impulse (symbolized by J or Imp) is the change in momentum of an object. If the initial momentum of an object is p1, and a subsequent momentum is p2, the object has received an impulse J:

Momentum is a vector quantity, so impulse is also a vector quantity.

Newton’s second law of motion states that the rate of change of momentum of an object is equal to the resultant force F acting on the object:

so the impulse J delivered by a steady force F acting for time Δt is:

The impulse delivered by a varying force is the integral of the force F with respect to time:

The SI unit of impulse is the newton second (N⋅s), and the dimensionally equivalent unit of momentum is the kilogram metre per second (kg⋅m/s). The corresponding English engineering unit is the pound-second (lbf⋅s), and in the British Gravitational System, the unit is the slug-foot per second (slug⋅ft/s).

YouTube Encyclopedic

  • 1/5
    Views:
    749 955
    1 009 512
    92 881
    371 514
    394 856
  • Introduction to Impulse & Momentum - Physics
  • Impulse and Momentum
  • What Are Momentum and Impulse? | Physics in Motion
  • Impulse Momentum Theorem Physics Problems - Average Force & Contact Time
  • Impulse

Transcription

Mathematical derivation in the case of an object of constant mass

Impulse J produced from time t1 to t2 is defined to be[1]

where F is the resultant force applied from t1 to t2.

From Newton's second law, force is related to momentum p by

Therefore,

where Δp is the change in linear momentum from time t1 to t2. This is often called the impulse-momentum theorem[2] (analogous to the work-energy theorem).

As a result, an impulse may also be regarded as the change in momentum of an object to which a resultant force is applied. The impulse may be expressed in a simpler form when the mass is constant:

where

  • F is the resultant force applied,
  • t1 and t2 are times when the impulse begins and ends, respectively,
  • m is the mass of the object,
  • v2 is the final velocity of the object at the end of the time interval, and
  • v1 is the initial velocity of the object when the time interval begins.

Impulse has the same units and dimensions (MLT−1) as momentum. In the International System of Units, these are kgm/s = Ns. In English engineering units, they are slugft/s = lbfs.

The term "impulse" is also used to refer to a fast-acting force or impact. This type of impulse is often idealized so that the change in momentum produced by the force happens with no change in time. This sort of change is a step change, and is not physically possible. However, this is a useful model for computing the effects of ideal collisions (such as in videogame physics engines). Additionally, in rocketry, the term "total impulse" is commonly used and is considered synonymous with the term "impulse".

Variable mass

The application of Newton's second law for variable mass allows impulse and momentum to be used as analysis tools for jet- or rocket-propelled vehicles. In the case of rockets, the impulse imparted can be normalized by unit of propellant expended, to create a performance parameter, specific impulse. This fact can be used to derive the Tsiolkovsky rocket equation, which relates the vehicle's propulsive change in velocity to the engine's specific impulse (or nozzle exhaust velocity) and the vehicle's propellant-mass ratio.

See also

Notes

  1. ^ Hibbeler, Russell C. (2010). Engineering Mechanics (12th ed.). Pearson Prentice Hall. p. 222. ISBN 978-0-13-607791-6.
  2. ^ See, for example, section 9.2, page 257, of Serway (2004).

Bibliography

External links

This page was last edited on 6 March 2024, at 21:28
Basis of this page is in Wikipedia. Text is available under the CC BY-SA 3.0 Unported License. Non-text media are available under their specified licenses. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. WIKI 2 is an independent company and has no affiliation with Wikimedia Foundation.