8.01x - Module 04.01 - Throw two objects at different times with different speeds. Do they collide. 

:)

yes that is correct

ask your high school peers.

watch the video again and answer the question at the very end

you can only contact me here

question unclear

Lectures by Walter Lewin. They will make you ♥ Physics. The function u used y as a function of t , can that function be used for similar type of question?

how many minutes into the video? What do you mean by a "similar type question"?

Lectures by Walter Lewin. They will make you ♥ Physics. The equation from 1:13 to 1:42.

Motion in direction R: at time t=0 object is at position R=R_o and it has velocity +v_o m/s and it is accelerated with +a m/s^2. R(t)=R_o + v_o*t + 0.5*a*t^2. I derive this in my lectures. Watch them.