Consider the acceleration,velocity,and displacement of a tennis ball as it falls to the ground and bounces back. The directions of which of these change during the process?

Two balls $A$ and $B$ are thrown with the same velocity $u$ from the top of a tower of height $h$. Ball $A$ is thrown vertically upwards and ball $B$ is thrown vertically downwards. If $t_A$ and $t_B$ are the respective times taken by the balls $A$ and $B$ to reach the ground,then identify the correct statement.

$A$ player throws a ball upwards with an initial speed of $29.4\; m s^{-1}$. What are the velocity and acceleration of the ball at the highest point of its motion?

$A$ ball is thrown vertically upwards from the top of a tower with a velocity $u$. This ball reaches the ground level with a velocity $4u$. The height of the tower is:

$A$ ball is dropped from a tower of height $80 \,m$. The time it takes to cover the last $50 \%$ of its fall is (acceleration due to gravity $= 10 \,ms^{-2}$)

$A$ ball is thrown vertically upwards with a speed of $10 \ m/s$ from the top of a tower $200 \ m$ high and another is thrown vertically downwards with the same speed simultaneously. The time difference between them in reaching the ground (in $s$) is: $(g = 10 \ m/s^2)$