v = u+a.t
U= initial velocity = 0
So v = a.t
a=4, t=8. Pop in the numbers and get the answer
Rearrange v=a.t to get
t =v/a
Velocity required = V = 36. a=4
Pop in the numbers and get the answer
For distance you have to use s=ut + 0.5a.(t.t) (t.t) = t squared
initial velocity u=0 so ut = 0
Rearrange to get
t = ????
Pop the numbers in to get the answer
To get the speed after that time, use v = a.t again as per the start of the question
Finally to get distance (s) travelled in the 3rd second, find out the speed at the start (t=2) of that second using the techniques above. That will be u, initial velocity for this part of the question.
Then use s=ut + 0.5 a(t.t) to get the distance, s.