The height of a building is 31.0m how tall is the building in kilometers

Standing side by side ,you and a friend step off a bridge at different times and fall for 1.6s to the water below.your friend goes first,and you follow after he has dropped a distance of 2.0m.when your friend hits the water,is the seperation between the two of you 2.0m or more than 2.0m? verify your answer with a calculation.

What is the measure of a change in an objects velocity?

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.