Question

The speed of an object in a particular direction is called ?

Answer 1

Here first we will know the difference between speed and velocity and then we will proceed to answer the question keeping in mind whether speed requires direction to describe or not.

Complete answer:
The distance travelled by an object in unit time is known as its speed. Since an object's distance travelled can never be negative or zero, its speed can't be either. Speed is always going to be a good thing. The body's velocities can vary, but the overall speed remains constant. The velocity may or may not be equal to the speed. A scalar quantity is speed.

The rate of change of displacement is called velocity, but displacement may be negative, positive, or zero. As a result, velocity may be either positive, negative, or zero. The speed of a moving object is indicated by its speed. The velocity of an object in motion indicates its speed as well as its location.

The quantity of velocity is a vector quantity. Both speed and velocity are measured in SI units $m/s$. Velocity is also the rate at which an object's location changes in relation to a frame of reference and time. In its most basic form, velocity can be described as the rate at which something moves in a specific direction.

The following are the characteristics of velocity:
-It's a scalar quantity.
-Since velocity is a vector quantity, it must have both magnitude (speed) and direction to be defined.
-The metre per second is the SI unit of velocity. It is expressed as $m{{s}^{-1}}$.
-Other units of velocity can be mph, $ft/s$.
-The dimension of velocity can be expressed as $L{{T}^{-1}}$.

If the degree or direction of a body's velocity changes, the body is said to be accelerating.The primary measure of an object's location as well as its speed is its velocity. For instance, a train travelling south at $60\,km/h$ would have a northbound velocity of $60\,km/h$. A straight object moving in a specific direction is said to have velocity. As a result, velocity refers to an object's speed in a specific direction.

Note: The main difference between speed and velocity is that speed is a scalar quantity so it cannot be negative whereas velocity is a scalar quantity, due to that it can be positive, negative or even zero.