Question

For a body starting from rest, what will be the ratio of the distance travelled by the body the 4th and 3rd second during its journey?

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

Answer 1

Answer: (A)

$\frac{7}{5}$

Using the relation $S_n=u+\frac{a}{2}(2n-1)$
As the body starts from rest,
$\therefore u=0$
So, $S_n=\frac{a}{2}(2n-1)$
$\therefore \frac{S_4}{S_3}=\frac{(2\times 4-1)}{(2\times 3-1)}=\frac{7}{5}$