Four particles $A, B, C$ and $D$ are moving with constant speed $v$ each. At the instant shown relative velocity of $A$ with respect to $B, C$ and $D$ are in directions

If a particle covers half the circle of radius R with constant speed then

A ring of mass $m$ moves from point $1$ to point $2$ along a smooth rigid horizontal wire with a constant speed $v$. The average force acting the ring over the time of its motion from $1$ to $2$ is

The radius of circle the period of revolution initial position and sense of revolution are indicated in the figure.

$y-$projection of the radius vector of rotating particle $\mathrm{P}$ is

A particle, moving with uniform speed $v$, changes its direction by angle $\theta$ in time $t$. Magnitude of its average acceleration during this time is

A particle $P$ is moving in a circle of radius $'a'$ with a uniform speed $v$ . $C$ is the centre of the circle and $AB$ is a diameter. When passing through $B$ the angular velocity of $P$ about $A$ and $C$ are in the ratio