Despite the use of diffrent types of measurement in our country

For standardization purposes

Explanation:

As the question mentions, there were different types of measurements in the country for the same things so measuring a thing in one type of measurement and then comparing it to another was quite cumbersome.

It also made comparing units with the rest of the world difficult. To combat this the SI system was introduced. It gave an international standard for measuring different things based on the metric system. This allowed for worldwide standardization and comparison as things could now be measured in the same units.

we need to know the time interval during which the force acts. impulse of force = momentum change