$A$ body thrown vertically upwards with an initial velocity $u$ reaches maximum height in $6$ seconds. The ratio of the distances travelled by the body in the first second and the seventh second is

$A$ stone dropped from the top of the tower touches the ground in $4 \, s$. The height of the tower is about..........$m$.

$A$ boy is standing on top of a tower of height $85 \, m$ and throws a ball in the vertically upward direction with a certain speed. If $5.25 \, s$ later he hears the ball hitting the ground,then the speed with which the boy threw the ball is .......... $m/s$ (take $g = 10 \, m/s^2$ and speed of sound in air $= 340 \, m/s$).

$A$ body is released from a great height and falls freely towards the earth. Another body is released from the same height exactly one second later. The separation between the two bodies,two seconds after the release of the second body is.......$m$

$A$ body at rest falls through a height $h$ with velocity $V$. If it has to fall down further for its velocity to become $3V$,the distance travelled in that interval is: (in $h$)

An iron block is dropped into a deep well. The sound of the splash is heard after $4.23 \, s$. If the depth of the well is $78.4 \, m$,find the speed of sound in air in $m/s$ $\left(g = 9.8 \, m/s^2\right)$.