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A force acting upon an object for some duration of time results in an impulse. The quantity impulse is calculated by multiplying force and time. Impulses cause objects to change their momentum. And finally, the impulse an object experiences is equal to the momentum change that results from it.
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.
The impulse-momentum theorem states that the change in momentum of an object equals the impulse applied to it. J = ∆p. If mass is constant, then… F∆t = m∆v. If mass is changing, then… F dt = m dv + v dm. The impulse-momentum theorem is logically equivalent to Newton's second law of motion (the force law). Units The SI unit of impulse ...
Describe momentum, what can change momentum, impulse, and the impulse-momentum theorem; Describe Newton’s second law in terms of momentum ; Solve problems using the impulse-momentum theorem
In lecture L9, we saw the principle of impulse and momentum applied to particle motion. This principle was of particular importance when the applied forces were functions of time and when interactions between particles occurred over very short times, such as with impact forces.
Relate impulses to collisions. Apply the impulse-momentum theorem to solve problems. We have defined momentum to be the product of mass and velocity. Therefore, if an object’s velocity should change (due to the application of a force on the object), then necessarily, its momentum changes as well.
Impulse, or change in momentum, equals the average net external force multiplied by the time this force acts: \[ \Delta p = F_{net}\Delta t.\] Forces are usually not constant over a period of time.
