Question

Chan is throwing a ball from the ground at an initial velocity of 22.1 meters per seconds. He threw the ball so high that on it's way down it got stuck in a tree 10 meters high. How long was the ball in the air before it got stuck in the tree?
a.4 sec
b.4.51 sec
c.24.9 meters
d.2.25 sec

Answer 1

The ball's height y at time t is

y = (22.1 m/s) t - 1/2 gt ²

where g = 9.80 m/s² is the magnitude of the acceleration due to gravity.

Solve for t when y = 10 m:

10 m = (22.1 m/s) t - 1/2 gt ²

→   t = 0.510 s or t = 4.00 s

The first time refers to when the ball first reaches 10 m on its way up, so t = 4.00 s and the answer is A.