Question

in the equation Sn=u + a(n - 1/2) , what does the subscript 'n' mean?

Answer 1

Explanation:

the equation

Sn=u+a/2(2n-1)

which is also sometimes written as

Sn=u+a(n-1/2)

it is used to calculate the displacement covered in nth second when the body is uniformly accelerated.

here,Subscript n denotes the nth second.

for example:

A body starts from rest and accelerates uniformly at the at rate of 2m/s².find the displacement covered in 3rd second.

Solution:

Given

u=0

a=2m/s²

n=3

so,the distance covered in 3rd sec=0+2(3-1/2)

=6-1

=5 m