What Initial Velocity would you have to give the Marble to make it hit the ground in 5 s

Traveling 381m in 5 seconds means the average velocity is: 381m/5s = 76.2 m/s.

Explanation:

Letting x be the initial velocity and v the final velocity, we have:

12(x+v)=76.2m/s

and (since v=x+50),

12(2x+50)=76.2m/s

x+25=76.2m/s

x=51.2m/s

-49 m/s

Explanation:

You would use the formula vf = vi + at, where vf stands for final velocity, vi stands for initial velocity, a stands for acceleration, and t stands for time. Assuming you're dropping the marble on Earth, the acceleration would be -9.8m/s², and the final velocity would be 0 m/s, as it stops after hitting the ground. (0 = vi + (9.8)(5))