A truck running at $90\, km h ^{-1}$ is brought to rest over a distance of $25\, m$. Calculate the retardation and time for which brakes are applied.

The average time taken by a normal person to react to an emergency is one$-$fifteenth of a second and is called the 'reaction time'. If a bus is moving with a velocity of $60\, km h^{-1}$ and its driver sees a child running across the road, how much distance would. the bus had moved before he could press the brakes ? The reaction time of the people increases when they are intoxicated. How much distance had the bus moved if the reaction time of the driver were $\frac{1}{2}\, s$ under the influence of alcohol ?

Draw a diagram to show the motion of a body whose speed remains constant but velocity continuously changes.

A cyclist driving at $36\, km h^{-1}$ stops his cycle in $2\, s$ by the application of brakes. Calculate $(i)$ retardation $(ii)$ distance covered during the application of brakes.

What do you understand by the displacement$-$time graph ? Draw a displacement-time graph for a girl going to school with uniform velocity. How can we calculate the uniform velocity from it ?