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

In the figure shown,find the velocity of the particle at point $P$ $(g = 10\,m/s^2)$.

An aeroplane flying $490 \, m$ above ground level at $100 \, m/s$ releases a block. How far on the ground will it strike (in $km$)?

An airplane is flying at a height of $1960 \, m$ with a horizontal velocity of $360 \, km/hr$. When the airplane is directly above point $A$,a body is dropped from it. How much time (in $sec$) will it take for the body to reach the ground?

An airplane is flying at a height of $490 \, m$ with a horizontal velocity of $60 \, km/h$. When the airplane is exactly above point $A$,a package is dropped from it. At what distance from point $A$ will the package hit the ground (in $/3 \, m$)? $(g = 9.8 \, m/s^2)$

There are three steps,each with a height of $10 \, cm$ and a width of $20 \, cm$. What minimum horizontal velocity (in $m/s$) must be given to a ball from the top step so that it clears all three steps?