MCQ
A particle initially at rest moves along the $x$-axis. Its acceleration varies with time as $a=4\,t$. If it starts from the origin, the distance covered by it in $3\,s$ is $...........\,m$
- A$12$
- ✓$18$
- C$24$
- D$36$
✓
Answer
Correct option: B.
$18$
b
$a=4 t$
$a=4 t$
Integrating,
$v=\frac{4 t^2}{2}=2 t^2$
again integrating
$d=\frac{2 t^3}{3}$
$t=3$
$d=\frac{2 \times 27}{3}=2 \times 9=18$
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