A student throws a set of keys vertically upward to her sorority sister, who is in a window 3.80 m above. The keys are caught 1.80 s later by the sister's outstretched hand. (b) What was the velocity of the keys just before they were caught?

Answer 1

average velocity=3.8/1.8 m/s

but avg velociyt=(Vf+vi)/2=(vf+vf-g*1.8)

solve for vf