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 ?
Ali while driving to school computes the average speed for his trip to be $20\, km h^{-1}$. On his return trip along the same route there is less traffic and the average speed is $30\, km h^{-1} .$ What is the average speed for Ali's trip ?
$(a)$ Differentiate between uniform linear and uniform circular motion.
$(b)$ Write any four examples of uniform circular motion.
$(c)$ Is uniform circular motion is accelerated motion ?
Draw a velocity versus time graph for a body which starts to move with velocity $'u^{\prime}$ under a constant acceleration $'a'$ for time $t$. Using this graph derive an expression for distance covered $'S'$ in time $'t^{\prime}$
A hiker rides $700\, m$ north, $300$ meast, $400 \,m$ north $600\, m$ west, $1200\, m$ south, $300\, m$ east and finally $100\, m$ north. Draw the path of motion of the biker. What distance did he cover ? What was his displacement ?