Question

A body starts from rest, what is the ratio of the distance travelled by the 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

Answer: (A)

$\frac{7}{5}$

Answer 2

Distance covered in $n^{th}$ second is given by
$S_n = u + \frac{a}{2} (2n - 1)$
Here, u = 0
$\therefore S_4 = 0 + \frac{a}{2} (2 \times 4 - 1)=\frac{7a}{2}$
$\, \, \, \, S_3 = 0 + \frac{a}{2} (2 \times 3 - 1)=\frac{5a}{2} \, \, \therefore \frac{S_4}{S_3}=\frac{7}{5}$