$A$ thief's car is moving with a speed of $10\,m/s$. $A$ police van chasing this car with a speed of $5\,m/s$ fires a bullet at the thief's car with a muzzle velocity of $72\,km/h$. Find the speed with which the bullet will hit the car in $m/s$.

Two particles having position vectors $r_1 = (3 \hat{i} + 5 \hat{j}) \text{ m}$ and $r_2 = (-5 \hat{i} - 3 \hat{j}) \text{ m}$ are moving with velocities $v_1 = (4 \hat{i} + 3 \hat{j}) \text{ m/s}$ and $v_2 = (a \hat{i} + 7 \hat{j}) \text{ m/s}$. If they collide after $2 \text{ s}$,then the value of $a$ is:

Two particles having position vectors $\overrightarrow{r_1} = (3\hat{i} + 5\hat{j}) \text{ m}$ and $\overrightarrow{r_2} = (-5\hat{i} - 3\hat{j}) \text{ m}$ are moving with velocities $\overrightarrow{v_1} = (4\hat{i} + 3\hat{j}) \text{ m/s}$ and $\overrightarrow{v_2} = (\alpha\hat{i} + 7\hat{j}) \text{ m/s}$. If they collide after $2 \text{ s}$,the value of $\alpha$ is:

Match Column-$I$ with Column-$II$ correctly.

Column-$I$	Column-$II$
$(1)$ Velocity of $A$ relative to $B$ if $A$ and $B$ are moving perpendicular to each other	$(a)$ $\vec{v}_{rm} = \vec{v}_r + \vec{v}_m$
$(2)$ Velocity of rain drops relative to a man	$(b)$ $\vec{v}_{AB} = \vec{v}_A + \vec{v}_B$
	$(c)$ $v_{AB} = \sqrt{v_A^2 + v_B^2}$

$A$ boat is moving with a velocity of $3\hat i + 4\hat j$ in a river,and the water is moving with a velocity of $-3\hat i - 4\hat j$ with respect to the ground. The relative velocity of the boat with respect to the water is:

$A$ particle is moving along the $x$-axis with its coordinate with time '$t$' given by $x(t) = 10 + 8t - 3t^2$. Another particle is moving along the $y$-axis with its coordinate as a function of time given by $y(t) = 5 - 8t^3$. At $t = 1 \; s$,the speed of the second particle as measured in the frame of the first particle is given as $\sqrt{v}$. Then $v$ (in $m^2/s^2$) is: