You throw a 20-n rock vertically into the air from ground level. you observe that when it is a height 16.0 m above the ground, it is traveling at a speed of 24.7 m/s upward.

The problem is missing some parts. But here are the questions and answers.

a.       Use the work-energy theorem to find its speed just as it left the ground 

Initial Kinetic Energy = GPE + KE

1/2 * m * V^2 = m * g * h + 1/2 * m * v^2

V^2 = 2 * 9.8 * 15.6 + 25.6^2

=sqrt 968.96

V (initial speed) ≈ 31.130 m/s

b.      Use the work-energy theorem to look for its maximum height. 

H = 968.96 / 2 * 9.8 ≈ 49.44 m

answer: option c.

explanation:

it has to be b, about 97 percent.