With what speed should a body be thrown upwards so that the distances traversed in the $5^{\text{th}}$ second and $6^{\text{th}}$ second are equal? (Take $g = 9.8 \, m/s^2$)

$A$ football is kicked into the air vertically upwards. What is its $(a)$ acceleration and $(b)$ velocity at the highest point?

$A$ ball is thrown vertically upwards. Which of the following plots represents the speed-time graph of the ball during its flight if air resistance is not ignored?

$A$ body is projected vertically upwards with a velocity $u$ from the top of a tower. The time taken by it to reach the ground is $n$ times the time taken by it to reach the highest point in its path. The height of the tower is:

$A$ body falls freely for $10 \ s$. What is its average velocity during this journey (in $m/s$)? (Take $g = 10 \ m/s^2$)

Reaction time: When a situation demands our immediate action,it takes some time before we really respond. Reaction time is the time a person takes to observe,think,and act. For example,if a person is driving and suddenly a boy appears on the road,then the time elapsed before he slams the brakes of the car is the reaction time. Reaction time depends on the complexity of the situation and on an individual.
You can measure your reaction time by a simple experiment. Take a ruler and ask your friend to drop it vertically through the gap between your thumb and forefinger. After you catch it,find the distance $d$ travelled by the ruler. In a particular case,$d$ was found to be $21.0 \; cm$. Estimate the reaction time in seconds. (in $; s$)