Question

A body started with velocity of $20{\text{ms}}^{-1}$ and moving with an acceleration of $2{\text{ms}}^{-2}$. The distance travelled by the body in the $8^{th}$ second is

• A. $35\text{m}$
• B. $20\text{m}$
• C. $45\text{m}$
• D. $30\text{m}$

Answer 1

The correct option is A $35\text{m}$

Given, $u=20{\text{ms}}^{-1},a=2{\text{ms}}^{-2},n=8$
As we know that the distance travelled by a particle in $n^{th}$ second is given as
$s_n=u+\frac{1}{2}a(2n-1)$
$\Rightarrow s_{8^{th}}=20+\frac{1}{2}\times 2(2\times 8-1)$
$\Rightarrow s_{8^{th}}=20+15$
$\Rightarrow s_{8^{th}}=35\text{m}$