Which of the following is the si unit used by chemists to measure the amount of an element or substance? a. mole b. atom c. molecule d. millimeter

Which of the following is the SI unit used by chemists to measure the amount of an element or substance?

mole

in one mole of anysubstance there are abou 6x10^23 molecules ... avogrado

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