Distance traveled by the object in n-th second

[niett]

Homework Statement

I dont understand what this mean lol

Relevant Equations

S = S_o + v_o + \frac{1}{2}at^2

Hi! I don't understand why is made the difference between the n second and the (n - 1) second. Can anyone help me? Thanks!

 

[haruspex]

Homework Statement:: I don't understand what this mean lol
Relevant Equations:: S = S_o + v_o + \frac{1}{2}at^2

View attachment 281778
Hi! I don't understand why is made the difference between the n second and the (n - 1) second. Can anyone help me? Thanks!

The distance traveled in the nth second is the distance traveled in the first n seconds minus the distance traveled in the first n-1 seconds.
But why anyone would bother to develop such an equation (to be remembered?) is beyond me, especially since it breaks down if using different units for time.