Question

A particle is moving with a velocity $35m/s$ along positive x-axis.It's acceleration is towards negative X-axis with the magnitude $4m/s^2$ then the distance covered by the particle in the $9th$ second:-

• A. $1m$
• B. $\frac{9}{8}m$
• C. $\frac{5}{4}m$
• D. $153m$

Answer 1

The correct option is A $1m$

$\begin{array}{c}\overrightarrow{u}=35m/s\hat{ı}\\ \overrightarrow{a}=4m/s^2\hat{ı}\\ S_a=u+\frac{1}{2}a(2n-1)\end{array}$

$\begin{array}{cc}{S}_a& =u+\frac{1}{2}a(2\times 9-1)\\ & =35+\frac{1}{2}\times \left(4\right)\times (18-1)\\ & =35+\frac{1}{2}\times (-68)\\ & =35-34\\ & =1m\end{array}$