Question

Define velocity. What is the SI unit of velocity
What is the difference between speed and velocity
Convert a speed of into m/s

Answer 1

Hint:Velocity is the total displacement covered in a particular period. It gives us an idea of how fast an object moves and in what direction it moves. That sums up the idea of velocity.
The difference between speed and velocity is speed is a scalar quantity and velocity is the vector quantity.

Formula Used:
\[velocity = \dfrac{{displacement}}{{time}}\]


 Complete step by step solution:
The proper definition for velocity is as follows:
Velocity is defined as the rate of change of the object’s position concerning a frame of reference and time.
Let us see an example:

Fig 1
In the figure, we can see that the total displacement covered is\[30{\text{ }}m\]. And let us take the time to be \[1\]minute. So the total velocity will be
Velocity= \[\dfrac{{30m}}{{60s}}\]
Velocity= \[0.5m/s\]
But velocity does not give only this. It also tells us the direction. So the proper answer will towards North.
The next question is what is the difference between speed and velocity? Before we go into the difference between speed and velocity we need to know about the difference between the distance and displacement.
Distance is the total amount of how much ground it covers during its motion. It’s a scalar quantity. Displacement on the other hand gives us total distance covered irrespective of its motion. It’s the object’s overall change in position
Speed is the distance covered over a period of time. And velocity is the displacement covered over a period of time including its direction.
The third question is to convert a speed into m/s
\[\dfrac{{1km}}{h} = \dfrac{{1000m}}{{3600s}}\]
First, we have to multiply the value mentioned in \[km/h\]by \[1000\]. This is to convert the numerator from kilometer to meter.
Then we have to divide the denominator by \[3600.\]This is to convert hours to seconds.
   \[\dfrac{{54}}{1} \times \dfrac{{1000}}{{3600}}\]
= \[15m/s\]

Note:
Let’s see an example

In the above example let us imagine that we have to travel from point A to point B. But unfortunately, due to some issues, we cannot take the shortest route, that is the\[\;20km\] route. Instead, we took the \[40km\]route. From this, we can see the difference between distance and displacement. Here the distance is \[40km\]. That is total ground that is covered during its motion. Her displacement is \[\;20km\]. That is the total distance covered irrespective of motion. This gives us the difference between speed and velocity.
The average velocity of an object is its total displacement divided by the total time taken. It can also be defined as the rate at which an object changes its position from one place to another.