See
http://www.jiskha.com/display.cgi?id=1253409013
A parachustist jumps from an airplane and freely falls y=51.8 m before opening his parachute. Thereafter, he decelerates at a=1.86 m/s^2. As he reaches the ground, his speed is 3.04 m/s.
a)How long was the parachutist in the air?
b)At what height did the parachutist jump from his plane?
2 answers
the answer is 7,040 J