A particle starts from rest with uniform acceleration and it's velocity after `n` seconds is `v`. The displacement of the body in last two seconds is.

Options

A. `(v(n + 1))/(n)`
B. `(2 v(n + 1))/(n)`
C. `(2 v(n - 1))/(n)`
D. `(v(n - 1))/(n)`

Answer

C

Explanation

`v = 0 + na rArr a = (v)/(n)`
displacement in last two seconds
`s(n) - s(n - 2)`
=`(0 + (1)/(2) an^2) - (0 + (1)/(2) a(n - 2)^2)`
=`2a(n - 1) = 2v ((n - 1))/(n)`.