# Impulse and Momentum

Impulse and Momentum

Defining Impulse and Momentum

• Momentum is a vector quantity and is described as the mass of an object multiplied by its velocity.
• Impulse is the product of the force applied to an object and the time during which it is applied.

Impulse-Momentum Theorem

• The Impulse-Momentum Theorem states that the change in momentum of an object equals the impulse exerted on it.
• In equation form, it is represented as: Ft = Δ(mv), where F is the force applied, t is the time, m is the mass of the object, and v is its velocity.
• If a net force is applied to an object, it will experience a change in momentum.

Impulse and Real-World Situations

• The concept of impulse can be applied in real-life situations. For example, when you catch a cricket ball, if you move your hand backwards on catching, you increase the time of contact which decreases the rate of change of momentum, leading to a smaller force on your hands.
• This concept is also used in safety technologies such as airbags and helmets, where they increase the time of impact, reducing the force experienced.

Conservation of Momentum

• The principle of conservation of momentum states that the total momentum of a closed system is constant if no external forces act upon it.
• This principle is applicable for all types of collisions – elastic, inelastic and perfectly inelastic.

Momentum during Collisions

• In elastic collisions, both momentum and kinetic energy are conserved, meaning the total momentum and kinetic energy before the impact is the same as after the impact.
• In inelastic collisions, only momentum is conserved, and some of the kinetic energy is lost to other forms such as sound, heat or deformation of the objects.
• In perfectly inelastic collisions, the two objects stick together and move as one after the impact, but the momentum remains conserved.

Momentum, Impulse and Forces

• The concepts of impulse and momentum are crucial in understanding how forces can affect the motion of an object.
• They allow us to calculate the forces involved in a collision or explosion and predict an object’s motion post an impact or force application.