(d)  In circular motion

$\vec{v}=\vec{w} \times \vec{r}$

since in circular motion a body changes its direction continually and hence changes its radial vector Now, If angular velocity $\vec{w}$ is constant then for the different radial vector $\left(\vec{r}_{1}, \vec{r}_{2}, \vec{r}_{3}\right)$ there will be different velocity of body $\left(i . e . \vec{v}_{1}, \vec{v}_{2}, \vec{v}_{3}\right)$ as shown in figure The centripetal acceleration of body will be to wards centre but for different position of body there will be different acceleration vector $\left(\vec{a}_{1}, \vec{a}_{2}, \vec{a}_{3}\right)$ as shown in fig momentum is given by $\vec{P}=m \vec{v}$

since velocity vector is changing hence, $\vec{P}$ will change In circular motion shown in figure $\left|\vec{r}_{1}\right|=\left|\vec{r}_{2}\right|=\left|\vec{r}_{3}\right|=r$ (radius of circle)

$\Rightarrow|\vec{v}|=|\vec{w}| r$

since $r$ and $|\vec{w}|$ is constant therefore $|\vec{v}|$ is constant for any position of body We know that kinectic energy $(k)$ $k=\frac{1}{2} m|\vec{v}|^{2}$

$\Rightarrow$ kinectic energy $(k)$ of body will be constant