QS Study

(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.

Example: 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.

Impulse = Force x time

Or, J = F x t

The impulse of force F acting over a time interval t is defined by the integral.

J = toF dt

The impulse of a force, therefore can be visualized as the area under the force versus time graph as shown in Figure. When a variable force acting for a short interval of time, then the impulse can be measured as,

J = Faverage x dt

Impulse of force is a vector quantity and its units is N s.

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