Question

Explain the meaning of the term speed.

Answer 1

Hint: You can approach the solution by thinking about the fact that speed is very frequently used and a rather simple idea to explain. Since velocity and speed are different and one of them is defined in correlation to the distance travelled while the other is correlated with the displacement happened, you are not supposed to confuse between them.

Complete step by step answer:
Speed is a rather simple and easy idea or concept to define. Basically, in physics, speed is the rate of covering of distance. In other words, speed can be defined as the distance which a moving body is covering in a unit time of the motion occurring. Notice that speed is defined as the distance covered per unit of time and not as the displacement happened per unit of time.
Let us suppose that a body or object travels a distance of $d$ meters in a given time of $t$ seconds. Then mathematically, we can define the average speed with which the particular object or body travelled as:
Speed $ = \dfrac{d}{t}\,m/s$
Speed is a scalar, as it can be seen from the formula we just derived that speed is nothing but a division of two scalars, hence, it is bound to be a scalar.
Since speed is a scalar it can never be negative in value and can only take either positive values when the distance travelled is positive, or a value $0$ when the body has performed no motion in the situation. No matter how small or in what directions, if a body is doing any motion, the speed will always have a positive value, unlike velocity, which can be negative or zero even if the motion is actually experienced by the body.

Note:A common mistake that many students make is that they define velocity instead of speed by claiming that speed is the ratio of displacement occurred and time taken for that displacement to happen. Speed and velocity are very different since velocity is the ratio of displacement occurred and time taken while speed is the ratio of distance travelled over the time taken to do so.