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 $g = 9.8 \, m/s^2$)

Two balls $A$ and $B$ are thrown with the same velocity $u$ from the top of a tower. Ball $A$ is thrown vertically upwards and ball $B$ is thrown vertically downwards. If $t_A = 6 \ s$ and $t_B = 2 \ s$,then the velocity $u$ of each ball is ....... $m/s$.

$A$ person sitting on the ground floor of a building notices through a window of height $1.5 \; m$ that a ball dropped from the roof of the building crosses the window in $0.1 \; s$. What is the velocity (in $m/s$) of the ball when it is at the topmost point of the window? (Take $g = 10 \; m/s^2$)

$A$ ball is thrown vertically upwards with a velocity $u$. What is the distance covered by it in the last $t$ seconds of its upward motion?

$A$ ball is thrown straight upward from the ground with a speed of $20 \,m/s$. The ball is caught on its way down at a point $5 \,m$ above the ground. The time taken by the ball during the entire trip is (assume $g = 10 \,m/s^2$):

$A$ body is thrown vertically up from the ground. It reaches a maximum height of $100\,m$ in $5\,sec$. After what time will it reach the ground from the maximum height position?