Q95 / 197 · NEET 2009 (Mains) · Physics
A particle starts its motion from rest under the action of a constant force. If the distance covered in first 10 seconds is $\mathrm{S}_1$ and that covered in the first 20 seconds is $\mathrm{S}_2$ then :
- A$\mathrm{S}_2=\mathrm{S}_1$
- B$\mathrm{S}_2=2 \mathrm{~S}_1$
- C$\mathrm{S}_2=3 \mathrm{~S}_1$
- Correct answerD$\mathrm{S}_2=4 \mathrm{~S}_1$
Solution
$\mathrm{s}=\frac{1}{2} \mathrm{at}^2$
$$
\begin{aligned}
& \frac{\mathrm{s}_2}{\mathrm{~s}_1}=\left(\frac{20}{10}\right)^2=4 \\
& \mathrm{~s}_2=4 \mathrm{~s}_1
\end{aligned}
$$
Hence, the correct answer is option: 'D'.