Physics, Kinematics, Free Fall (7 of 12) Initial Velocity for Known Time in the Air

Links to my other free fall videos below:
(1) Free Fall: An Explanation
(2) Solving for Time to Fall from a Known Height
(3) Solving for Final Velocity from Known Time to Fall
(4) Solving for Height from Known Time to Fall
(5) solving for Final Velocity when Falling from a Known Height
(6) Solving for Maximum Height when Launched Up with a Known Initial Velocity
(7) Solving for Initial Velocity Needed to Reach a Known Height
(8) Solving for Total Time in the Air when Launch Up with a Known Initial Velocity
(9) Solving for Initial Velocity when form a Known Total Time in the Air
(10) Solving for Maximum Height when Launch Up from a Surface Above the Ground
(11) Solving for Total Time in the Air when Launch Up from a Surface Above the Ground
(12) Solving for Final Velocity when Launch Up from a Surface Above the Ground

[julioequinones]

super clear the only thing I would have done is remind people that the reason the total time is 6 even though we used half was because the ball has to come back down and that's why the total time is 6

[jaykantkumar]

an object is dropped from height=h with some initial velocity. if it covers 1/4th of its distance in 1/2 time taken and 1/2 distance is covered in 6√2 second. find h.

[Zypher_desu]

If only the questions given in the actual quiz would be this easy ...

[hoshicakes]

Why did you put the acceleration 9.81m/s^2 negative ? Since it's going on the direction of the positive y Axis then shouldn't it be positive ?

[yuriezelshin]

Thumbs up! Exam 2morrow, i hope this can help me :)
I put all of my hopes in ur lessons :)

[oceanclementine]

Great video as always! Really helped me! Thanks a lot

[إسماعيل-طخض]

Makes zero sense. Thank you very much.

EDIT: Now I get it. Thank you very much.

[TQprincess]

Thanks alot .This question take my lot of time but with help of Allah Almighty and your video make it easy

[nmslmatachuan]

Thank you very much sir for your time and effort to help us! Could you please make some tutorial videos regarding college level physics with calculus 1 course? Thank you!

[hizkiapermata]

i watched the whole video from 1 to 7 and i now understood the formula and the concepts of it. This video helped me a lot and i understood instantly after watching it compare to my online studies.

Keep Up And i love your tutorials

[demosdown]

What if you were to say that you start at a specific height say 15ft above the ground. You throw the object up, and 5 seconds later it hits the ground. What then would be the initial velocity?

[UNCFan-dlzx]

Thanks for the Help it's much appreciated!

[scott.miller]

You took a complicated concept and explained it very clearly. Thank you!

[harukazuto]

There's just I want to know, why us the acceleration is -9.81 m/s² ?

[cameronbrilla]

Thank you so much for this. Extremely helpful!

[Faith-ehfq]

Thank you so much, This is year 2020 Corona virus. My college moved my physics classes Online and your videos have truly helped me .

Bless you

[aestheticsupremacy]

Vi= -at?....How did "A" become negative?