Two students are on a balcony 21.4 m above the street. One student throws a ball ver- tically downward at 15.

Two students are on a balcony 21.4 m abovethe street. One student throws a ball ver-tically downward at 15.8 m/s; at the sameinstant, the other student throws a ball verti-cally upward at the same speed. The secondball just misses the balcony on the way down.What is the velocity of the first ball as itstrikes the ground?Answer in units of m/s