For the acceleration-time $(a-t)$ graph shown in figure, the change in velocity of particle from $t=0$ to $t=6 \,s$ is ........ $m / s$

Give important factor to control the speed of vehicle in area of school or hospital.

A particle moves for $8\, seconds$. It first accelerates from rest and then retards to rest. If the retardation be $3\, times$ the acceleration, then time for which it accelerates will be 

The velocity $(v)-$ time $(t)$ plot of the motion of a body is shown below:

(image)

The acceleration $(a)-$ time $(t)$ graph that best suits this motion is :

An object, moving with a speed of $6.25\, m/s$, is decelerated at a rate given by

$\frac{{dv}}{{dt}} =  - 2.5\sqrt v$

where $v$ is the instantaneous speed. The time taken by the object, to come to rest, would be ........$s$

An object with a mass $10 \,kg$ moves at a constant velocity of $10 \,m/sec$. A constant force then acts for $4\, second$ on the object and gives it a speed of $2\, m/sec$ in opposite direction. The acceleration produced in it, is ........ $m/{\sec ^2}$