The numerical ratio of displacement to distance for a moving object is

$A$ person is running along a circular path in a park.
$(a)$ At what point does he change his direction while running?
$(b)$ If he covers half of the circular path,what will be his displacement? Draw a diagram showing it.

Two cars $A$ and $B$ have their displacement-time graph as given below. Which car has a greater velocity?

Give one example for each of the type of motion when
$(i)$ acceleration is in the direction of motion.
$(ii)$ acceleration is against the direction of motion.
$(iii)$ acceleration is uniform.

The average time taken by a normal person to react to an emergency is $1/15$ of a second and is called the 'reaction time'. If a bus is moving with a velocity of $60 \, km/h$ and its driver sees a child running across the road,how much distance would the bus have moved before he could press the brakes? The reaction time of the people increases when they are intoxicated. How much distance would the bus have moved if the reaction time of the driver were $1/2 \, s$ under the influence of alcohol?

From the given $v-t$ graph (Fig.),it can be inferred that the object is