The unit of density is called derived
unit, why ?

The unit of density is called derived unit because it depends on fundamental units like kilogram,metre and second.

Hope,it will helpyouu!

here we know that ball will drop down by total distance 3.2 m

so here we know that

now using kinematics

now in the same time it will cover horizontal distance of 0.75 m

so speed of the ball will be