Wednesday, 20 April 2016

Impulsive force and Impulse of a force

Impulsive  force  and  Impulse  of  a  force

(i)  Impulsive  Force
An impulsive force is a very great force acting for a very short time
on a body, so that the change in the position of the body during the time
the  force  acts  on  it  may  be  neglected.
(e.g.) The blow of a hammer, the collision of two billiard balls etc.

(ii)  Impulse  of  a  force
The  impulse  J  of  a  constant  force  F
acting for a time t is defined as the product
of  the  force  and  time.
(i.e)  Impulse  =  Force×time
               J=F×t
The impulse of force F acting over a time interval t
is  defined  by  the  integral,

J=F∫dt  (0 to t)

When a variable force acting
for  a  short  interval  of  time,  then  the  impulse  can  be  measured  as,
J  =  F average×dt