Question

A body starts from rest. What is the ratio of the distance travelled by the body during the $4^{th}$ and $3^{rd}$ second ?

• A. $\frac{7}{5}$
• B. $\frac{5}{7}$
• C. $\frac{7}{3}$
• D. $\frac{3}{7}$

Answer 1

The correct option is A $\frac{7}{5}$

Given, $u=0$
As we know that the distance travelled by a particle in $n^{th}$ second is given as
$S_n=u+\frac{a}{2}(2n-1)$
Thus, ratio of distance travelled in $4^{th}$ sec to $3^{rd}$ sec is
$\frac{S_{4^{th}}}{S_{3^{rd}}}=\frac{0+\frac{a}{2}(2\times 4-1)}{0+\frac{a}{2}(2\times 3-1)}=\frac{2\times 4-1}{2\times 3-1}=\frac{7}{5}$