What is the distance covered by a freely falling body in the first second (in $m$)? $(g = 10 \ m/s^2)$

$A$ balloon starts rising from the ground from rest with an upward acceleration of $2 \, m/s^2$. Just after $1 \, s$,a stone is dropped from it. The time taken by the stone to strike the ground is nearly ....... $s$.

If a stone thrown vertically upwards from a bridge with an initial velocity of $5 \,m \,s^{-1}$ strikes the water below the bridge in a time of $3 \,s$, then the height of the bridge above the water surface is (Acceleration due to gravity $= 10 \,m \,s^{-2}$) (in $\,m$)

The given figure shows the $x-t$ plot of one-dimensional motion of a particle. Is it correct to say from the graph that the particle moves in a straight line for $t < 0$ and on a parabolic path for $t > 0$? If not,suggest a suitable physical context for this graph.

$A$ diving board is at a height of $h$ from the water surface. $A$ swimmer standing on this board throws a stone vertically upward with a velocity of $16 \,ms^{-1}$. It reaches the water surface in a time of $5 \,s$. In the next $0.2 \,s$, the diver hears the sound from the water surface. What is the speed of sound (in $\,ms^{-1}$)? (Take acceleration due to gravity $g=10 \,ms^{-2}$)

$A$ body is thrown vertically upwards with velocity $u$. The distance travelled by it in the fifth and the sixth seconds are equal. The velocity $u$ is given by.........$m/s$ $(g = 9.8\, m/s^{2})$