Impulse

Impulse Definition

Impulse is a quantity which defines the effect of a net force acting on an object.

A large force which acts for a short time to generate a finite change in the momentum is known as an impulsive force.

Impulse Formula

An impulse of a force is the change in momentum produced by the force. The impulse is equal to the product of the force and the time during which it acts. Therefore, when a large force acts for a short time, momentum acts to produce a finite change in momentum of the body, and the force acting on the body is called force of impulse or impulsive force. 

Hence, the impulse formula can be given

Impulse = Force Time

Unit of Impulse

Impulse is a term which quantifies the overall effect of a force acting over time. Impulse is given by the symbol j⃗. The impulse is equal to the product of the force and the time during which it acts.

Hence the SI unit of impulse is 

Impulse = Force Time

Impulse = Newton seconds

Impulse = N-s

Thus, the SI unit of Impulse is Newton-second (N-s).

Impulse is a vector quantity which means that it has both direction as well as magnitude. The direction of impulse is same as the direction of F⃗.

Momentum

The word momentum is mainly used in sports. When a player has momentum, it means that they are moving and are difficult to stop. A body with momentum can be stopped when a force is applied against the direction of the body for some time. 

The momentum is given as

P=M{V}

Here

P = Momentum

M = mass

V = velocity

Hence, from the above equation, we can define momentum as the product of mass and velocity.

When the force is higher, more force is required to stop the body.

The SI unit of momentum is kg.m.s-1

From the above equation, when the velocity of a body changes, the momentum of the body also changes.

Impulse Equation

The impulse is equal to the product of the force and the time during which it acts.

Hence, the impulse equation can be given

Impulse=Force (final time-initial time)

I={F}t

Here,

I = impulse

F = force

T = time

Impulse – Momentum Theorem

The impulse momentum theorem helps us to understand the relation between impulse and momentum. According to the impulse momentum theorem the change of momentum observed in an object is equal to the amount of impulse applied to the object.

Impulse determines the changes of momentum.

The impulse momentum equation is

{j} ={p2} -{p1}

Here,

{p1}= Initial momentum

{p2}= final momentum

Specific Impulse

Specific impulse is the determination of efficiency of rocket fuels. Specific impulse is defined as the impulse per mass (or thrust per mass flow rate). Specific impulse is equal to exhaust velocity. The SI unit of Specific impulse is meter per second.

Real Life Instances

We meet the impulse at different situations in our daily life. Some of which are given below-

• Airbags in cars are designed according to the principle of Impulse

• Tossing the coin is also an example of impulse

• Hitting a golf ball is another example of impulse

• Batsman hitting the ball while playing the cricket match is the best example of impulse