Why would you want to know the speed of an object

Because when something is moving  such as a car if your going too fast there could be a crash or collision.

Explanation:

see earlier

first thing first of the answer is with technology. second thing second thing is that the big bang theory did not happened u see they say it did but what they dont realize is that like dinasures are still a round they might deny it but they and look at these 12 foot human skelteons they find lets see didnt the bible say something about giants. hope this peace.