# Impulse

### Definition of Impulse

• In physics, impulse is a vector quantity that represents the introduction or removal of momentum from a system.
• It is the product of a force, F, and the time period, t, over which it acts.
• The SI unit of impulse is the newton second (N s), which is equivalent to a kilogram meter per second (kg m/s).
• Mathematically, it is defined as Impulse (J) = Ft, where ‘F’ is the force and ‘t’ is the time interval over which the force is applied.

### Impulse and Momentum Change

• Impulse is directly linked to the change in momentum of an object or system. An impulse can either increase or decrease the momentum of an object depending on the direction of the force being applied.
• The formula J = Δp illustrates this relationship, where ‘Δp’ stands for the change in linear momentum.
• The force (F) applied to an object for a time (t) will result in a change of momentum (p), hence J= Δp= Ft.

### Impulse in Collisions

• Impulse is a crucial factor in understanding the behaviour of objects during collisions. From a physics standpoint, collisions involve exchanges of momentum and impulses.
• In the context of collisions, if two objects interact, the total impulse experienced is the same for both objects but in opposite directions.
• Applying the principle of conservation of momentum and using the relationship between impulse and momentum allows us to solve numerous real-world problems.

### Applications of Impulse

• Knowledge of impulse is essential for designing vehicles, sporting equipment, and other technologies where impact forces must be managed.
• Understanding impulse is particularly useful in sports science, as it explains why a cricketer ‘follows through’ when bowling, or a golfer swings their club in a full arc.
• Engineers also use the concept of impulse when designing safety mechanisms like airbags and crumple zones in cars.

### Understanding Impulse

• Understand the mathematical relationship between Impulse, Force, and Time.
• Grasp how this relationship is linked with the change in momentum of an object.
• Have a firm grasp on the concepts of impulse in collisions and leverage them to solve collision-related problems.
• Be able to apply these principles in real-world situations and understand the need for impulse in various fields.

Impulse is a critical concept when investigating collisions, momentum changes, and the effects of forces applied over time. Comprehending how impulse influences these areas is vital for both theoretical physics and practical applications.