Question

Sn = u + a(n-1/2) how this is came​

Answer 1

please refer to attachment

Answer 2

Answer:

we know that the distance travelled in n seconds is Sn= un + 1/2 an^2

and distance travelled in n+1 seconds is

Sn+1 = un + 1/2 a(n+1)^2

So the distance travelled in nth second is

Sn — Sn+1

Which comes out to be

u + a(2n+1) /2

where u is initial speed n is nth second and a is acceleration.

Explanation:

You should have the knowledge of 2nd eqn. to get this

Hope it helps!