You throw a tennis ball straight up (neglect air resistance). It takes 7.0 seconds to go up and then return to your hand. How fast did you throw the ball?

Velocity of throwing = 34.335 m/s

Explanation:

Time taken by the tennis ball to reach maximum height, t = 0.5 x 7 = 3.5 seconds.

Let the initial velocity be u, we have acceleration due to gravity, a = - 9.81 m/s² and final velocity = 0 m/s

Equation of motion result we have v = u + at

Substituting

0 = u - 9.81 x 3.5

u = 34.335 m/s

Velocity of throwing = 34.335 m/s