$A$ car covers the first half of the distance between two places at $40 \text{ km/h}$ and the second half at $50 \text{ km/h}$. The average speed of the car is (in $text{ km/h}$)

Five particles have speeds $1, 2, 3, 4, 5 \, m/s$. The average velocity of the particles is (in $m/s$):

In $1.0 \, s$,a particle moves from point $A$ to point $B$ along a semicircle of radius $1.0 \, m$ (see figure). The magnitude of the average velocity is ......... $m/s$.

The position of an object moving along the $X$-axis is given by $x = \alpha + \beta t^2$, where $\alpha$ and $\beta$ are constants with appropriate dimensions and $t$ is time in seconds. The average velocity between $t = 2 \ s$ and $t = 4 \ s$ is $12 \ m/s$. If $\alpha = 8 \ m$, then the value of $\beta$ is: (in $m/s^2$)

$A$ train has a speed of $60\, km/h$ for the first one hour and $40\, km/h$ for the next half hour. Its average speed in $km/h$ is

$A$ car moves a distance of $200 \; m$. It covers the first half of the distance at a speed of $40 \; km/h$ and the second half of the distance at a speed of $v$. If the average speed is $48 \; km/h$,the value of $v$ is: (in $; km/h$)