Question

why does a sheet of paper fall slower than one that is crumpled into a ball

Answer 1

because the crumpled ball has less area of surface than the sheet of paper .As we know , greater the area of surface less the friction is... So , friction (of air )acts more on sheet of paper than that on crumpled ball.

Answer 2

a sheet of paper occupies more volumeas compared to crumpled paper so some forces act upon crumpled so iy falls down quickly than a sheet of paper