A parachutist descending at a speed of 20.0 m/s loses a shoe at an altitude of 20.0 m. (Assume the positive direction is upward.) a)When does the shoe reach the ground? (seconds) b)What is the velocity of the shoe just before it hits the ground?
i used Vf=square root(vi2 + 2ax) or Vf=squareroot(20squared+2*20*-9.81)
for t i used t =Vav/a but i don't think that's a correct equation
The Attempt at a Solution
for Vf, i got 2.76 m/s and for time i got 1.16 s
But i know the time is definitely wrong because it has to be less than 1 second since both speed and distance are 20.0