Impulse - Definition, Formula, Examples
Impulse
A large force acting for a very short interval of time is called as ‘Impulsive force’. When a force F acts on a body for a period of time t, then the product of force and time is known as ‘impulse’ represented by ‘J’
Impulse, J = F × t (1.7)
By Newton’s second law
F = Δp / t (Δ refers to change)
Δp = F × t (1.8)
From 1.7 and 1.8
J = Δp
Impulse is also equal to the magnitude of change in momentum. Its unit is kg m s–1 or N s. Change in momentum can be achieved in two ways. They are:
i. a large force acting for a short period of time and
ii. a smaller force acting for a longer period of time.
Examples:
- Automobiles are fitted with springs and shock absorbers to reduce jerks while moving on uneven roads.
- In cricket, a fielder pulls back his hands while catching the ball. He experiences a smaller force for a longer interval of time to catch the ball, resulting in a lesser impulse on his hands.
