Acceleration in 1D

Q. The acceleration of a particle is defined by the relation, $a=-4x(-1+\frac{1}{4}{x}^2)$ , where $x$ is displacement along $x-$ axis. All the quantities are in $SI$ units. If velocity of the particle $\left(v\right)=17\text{m/s}$ when $x=0$, then the velocity of the particle when $x=4\text{m}$ is

1. $12\text{m/s}$
2. $15\text{m/s}$
3. $20\text{m/s}$
4. $25\text{m/s}$

Q. The figure shows the v - t graph of a particle moving in straight line. Find the time (in $s$) when particle returns to the starting point.

Q. The acceleration of a particle is defined by the relation, $a=-4x(-1+\frac{1}{4}{x}^2)$ , where $x$ is displacement along $x-$ axis. All the quantities are in $SI$ units. If velocity of the particle $\left(v\right)=17\text{m/s}$ when $x=0$, then the velocity of the particle when $x=4\text{m}$ is

1. $12\text{m/s}$
2. $15\text{m/s}$
3. $20\text{m/s}$
4. $25\text{m/s}$