Question

What is an impulse? Write the S.I. unit and dimensional formula of impulse.

Answer 1

Recall the concept of momentum. The property of any moving object by the virtue of its mass and motion is known as momentum. It is the product of the mass of the object and the velocity with which it is moving. If the net external force on an object is zero, then the momentum of the system is constant.

Complete step by step solution:
Step I:
Impulse is defined as a quantity that describes the effect of force acting on an object for a particular period of time. It is a vector quantity, since it has both magnitude and direction. It is represented by using the symbol ‘J’.

Step II:
Mathematically, impulse is represented as the product of the force acting on the object and the time for which it is acting.
Therefore, it can be written as

$J = F.\Delta t$

Step III:
When an impulse is applied to an object, then it changes the linear momentum of the vector in the same direction. The S.I. the unit of impulse is Newton Second and it is represented by the symbol (N-s).

Note: It is to be noted that if a very large force is acting on an object for a very short period of time, then it will have a great effect on the momentum of the body. Also according to the impulse momentum theorem, the change in the momentum of an object is equal to the impulse applied to it. The impulse momentum theorem is also known as the force law, which is equivalent to Newton’s second law of motion.