As kids, we all loved racing.

Faster people won the race while the slower ones lost.

To know how fast or slow a person moves, we define their “speed”.

For example, Usain bolt covered 100 meters in 8.5 seconds in the Olympics.

Whereas a cheetah can cover 100 meters in only 6 seconds.

The cheetah and Bolt, both traveled 100 meters but the cheetah took lesser time, making it faster than Bolt.

It is clear that the speed depends on both time and distance.

If you cover more distance in the same time, it means you are faster.

Whereas if you take more time to cover the same distance, you are slower.

In other words, speed depends on the distance per unit time.

Mathematically, it can be represented like this.

Whenever we define a physical quantity, we must also define its unit.

The unit of speed.

Since the SI unit of distance is ‘meters/m’ and the SI unit of time is ‘seconds/sec’. So we can say that the SI unit of speed is m/sec.

Time for a quick Recap

Speed is defined as the distance traveled per unit time.

The SI unit of speed is meters/seconds.

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