Question

A particle covers $150\, m$ in $8^\text{th}$ second starting from rest, its acceleration is:

• A. $15\, ms^{-2}$
• B. $20\, ms^{-2}$
• C. $10\, ms^{-2}$
• D. $8\, ms^{-2}$

Answer 1

Answer: (B)

$20\, ms^{-2}$

Answer 2

From equation of motion, we have $s=u t+\frac{1}{2} a(2 n-1)$ where $u$ is initial velocity, $t$ is time, $a$ is acceleration and $n$ is the particular second. Since $u=0$, we have $150 =0+\frac{1}{2} a(2 \times 8-1)=\frac{15 a}{2}$ $\Rightarrow a \neq \frac{300}{15}=20 \,m / s ^{2}$