IMPULSE
If a force acts on a body for a short time interval, then the product of force and its time of action, is called impulse of the force.
i.e. Impulse = Force × time interval
By Newton’s second law 
i.e Impulse = Change in momentum
Thus impulse of a force is equal to the change in momentum produced by the force.
- The SI unit of impulse is Ns.
- A large force acting for a short time to produce a finite change in momentum is called an impulsive force. Impulsive force is like any other force – except that it is large and acts for a short time.
Calculation of Impulse for Variable Force
Graphical Method:
(A) For constant Force:
In this case F versus t graph is a straight line parallel to the x – axis (time- axis)
Area under the f – t graph
= area of rectangle abcd
= ad x dc
= f .[t2 – t1] = F. Δt
= Impulse
(B) For variable force
In this case F – t graph is a curve. Let us divide the whole area under the graph into thin strips width of each strip represent small time-interval and the average height of the strip represents the force F. So, area of each strip represents the small impulse by the force for small displacement.
Total area under F – t graph
= Sum of area of all the strips
= Sum of impulse for all these small time-intervals
= Total Impulse.
Thus, graphically, the impulse is the area between the force curve and the time axis, as shown in figure.
Calculus Method:
If the value of force varies with time [t] i.e. F = f(t) then the work done by variable force is given by
Impulse Video
In Hindi + English Mix
Numerical Examples on Impulse
Law of Conservation of Linear Momentum
Law of Conservation of Linear Momentum
In Hindi + English Mix
