$A$ body is projected vertically upward with speed $10 \, m/s$ and another at the same time with the same speed in the downward direction from the top of a tower. The magnitude of the acceleration of the first body with respect to the second is ...... $m/s^2$ (take $g = 10 \, m/s^2$).

$A$ bus is moving with a speed of $10\; m/s$ on a straight road. $A$ scooterist wishes to overtake the bus in $100\; s$. If the bus is at a distance of $1\; km$ from the scooterist,with what speed should the scooterist chase the bus? (in $m/s$)

$A$ motor car moving at a speed of $72 \, km/h$ cannot come to a stop in less than $3.0 \, s$,while for a truck,this time interval is $5.0 \, s$. On a highway,the car is behind the truck,both moving at $72 \, km/h$. The truck gives a signal that it is going to stop in an emergency. At what distance should the car be from the truck so that it does not bump into (collide with) the truck? The human response time is $0.5 \, s$.

$A$ ball is dropped from the top of a building $100\,m$ high. At the same instant,another ball is thrown upwards with a velocity of $40\,m/s$ from the bottom of the building. The two balls will meet after $..........\,s$.

$A$ motor car moving at a speed of $72\, km/h$ cannot come to a stop in less than $3.0\, s$ while for a truck this time interval is $5.0\, s$. On a highway,the car is behind the truck,both moving at $72\, km/h$. The truck driver signals an emergency stop. At what minimum distance should the car be from the truck so that it does not collide with the truck? The human response time is $0.5\, s$.

On a foggy day,two drivers spot each other when $80\, m$ apart. They were travelling at $70\, km/h$ and $60\, km/h$. Both apply brakes simultaneously which retard the cars at the rate of $5\, m/s^2$. Which of the following statements is correct?