Question

a particle starrs moving with acceleration 2m/s^2 . distance travelled by it 5th half second is

Answer 1

9m.... solve it by nth formula
u+a/2(2n-1)

Answer 2

Yes I thought in this way. But we can see this in this way also: we have to find distance in 5th ​half second.

Formula: s=ut+(1/2)a(t^2) 

t^2 = (5/2)^2 – ​(2)^2 = 2.25 and using this in our formula distance travelled is: 2.25m