Two objects, object X and Object Y, are held together by a light string

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

the assestment will probley apele with cause and effect

the doppler effect is used by weather forecasters to measure 

moving clouds