why do we need to measure a object  

Measurement is used in all aspects of daily life, as well as in such fields as engineering, architecture, and medicine. It is not only a key engineering, science, physics and economics but it is our world.
Everything has mass and takes up measured volume and spaces. 
 
In our daily life, we measure things every day.
In the morning a person may have weighed himself, poured two cups of water into the coffeemaker, checked the temperature outside to help to decide what to wear, cut enough gift wrap off the roll to wrap a present, decided on the size of a storage container for some leftover food, noted on his car’s odometer how far he had driven, monitored both his car’s traveling speed and its gas gauge, and kept an eye on the time so that he would not be late.
 
Our modern world would not exist if we could not or did not measure and measure to a standard consistently and to a high degree of accuracy.
For example, the computers have parts that are measured to 0.000000000001 inch. We would have no computers, TV, iPod, GPS if we could not measure it,.

To live in our physical world one need to understand it. The measurement is key to that knowledge and interaction.
Newton discovered gravity and later scientist measured the "acceleration" of earth’s gravity.
That lead to understanding how FORCE and acceleration and mass relate. Without measurement this could not have been possible at all.
 

  • 2
ans....We measure things so that we all agree on their properties. We can communicate, trade, experiment, duplicate and otherwise function as an inter relational society. Simply because we have a universal standard which we all understand.
  • 2
What are you looking for?