Question

the terminal velocity of a tennis ball is about 21 m/s. a tennis ball is dropped from a hot air balloon. how fast will it be moving after falling for 10 s? 21m/s, 77m/s, 9.8m/s, or 98m/s.

Answer 1

v = g t = 9.81 * 10 = 98.1 if no air drag
but with friction terminal speed is 21
so
21 m/s