Question

If the final velocity of a moving body is less than its initial velocity. What type of motion does the body perform?

Answer 1

Hint: First of all, we have to understand what final velocity of a body refers to. Also we have to look into what initial velocity corresponds. We have to find the relation of the velocity of the particle with the acceleration of the particle. Then we will find the nature of motion that it will possess.

Complete step by step answer:
Velocity of a particle refers to the displacement that a particle covers with a certain amount of time. Velocity is a vector quantity which means that it has both magnitude and direction.Final velocity of a particle or body refers to the velocity which it attained at the last moment of time till which it is calculated.

Initial velocity refers to the velocity which it gained while it started or considered to be the moment of time of starting.From the motion equation we find,
$v = u + at$
$ \Rightarrow a = \dfrac{{v - u}}{t}$
Where $v$ corresponds to the final velocity of the particle, $u$ refers to the initial velocity of the particle, $t$ is the time period and $a$ refers to acceleration.

Acceleration of the particle is the time rate of change of velocity. Now, according to the question the final velocity of the particle is less than the initial velocity. So, the acceleration will be a negative quantity.It means that the speed of the particle is decreasing with time.When acceleration decreases of a particle or has a negative value, then such type of motion is known as retarding motion.

Note: It must be noted that acceleration is also a vector quantity as it is directly dependent on velocity of a particle which is also a vector quantity. When the acceleration of a particle increases with time, meaning the final velocity is more than the initial velocity, such type of motion is called accelerating motion.