Answer
Nicole threw the ball with a speed of 14 m/s
Work Step by Step
Since the ball passes Chad with a speed of 10 m/s on the way down, the ball had a speed of 10 m/s when it passed Chad on the way up. We can find the initial speed of the ball as;
$v_0^2 = v^2-2ay$
$v_0 = \sqrt{v^2-2ay}$
$v_0 = \sqrt{(10~m/s)^2-(2)(-9.8~m/s^2)(5.0~m)}$
$v_0=14~m/s$
Nicole threw the ball with a speed of 14 m/s.
