$A$ plane is flying horizontally at $98 \, m/s$ and releases an object which reaches the ground in $10 \, s$. The angle made by the object with the horizontal while hitting the ground is ......... $^o$.

$A$ ball is projected from a point $O$ as shown in the figure. It will strike the ground after ........ $s$ $\left(g=10 \, m/s^2\right)$.

From a tower of height $h$,one ball is thrown downwards with a velocity $u$ and another ball is thrown horizontally with the same velocity $u$. What is the ratio of their velocities when they reach the ground?

$A$ ball is thrown from a rooftop at an angle of $45^\circ$ above the horizontal. It hits the ground a few seconds later. At what point during its motion does the ball have $(a)$ greatest speed, $(b)$ smallest speed, and $(c)$ greatest acceleration? Explain.

$A$ man runs across the roof of a tall building and jumps horizontally with the hope of landing on the roof of the next building,which is at a lower height than the first. If his speed is $9 \, m/s$,the horizontal distance between the two buildings is $10 \, m$,and the height difference is $9 \, m$,will he be able to land on the next building? (Take $g = 10 \, m/s^2$)

$A$ ball is projected upwards from the top of a tower with a velocity of $50 \, ms^{-1}$ making an angle of $30^{\circ}$ with the horizontal. The height of the tower is $70 \, m$. After how many seconds from the instant of throwing will the ball reach the ground?