$A$ stone is dropped into water from a bridge $44.1 \ m$ above the water. Another stone is thrown vertically downward $1 \ s$ later. Both strike the water simultaneously. What was the initial speed of the second stone in $m/s$?

$A$ ball is thrown vertically upwards. Which of the following plots represents the speed-time graph of the ball during its flight if air resistance is not ignored?

Consider a rubber ball freely falling from a height $h = 4.9 \ m$ onto a horizontal elastic plate. Assume that the duration of collision is negligible and the collision with the plate is totally elastic. Then the velocity as a function of time and the height as a function of time will be represented by which of the following graphs?

$A$ body falling from a high minaret travels $40 \ m$ in the last $2 \ s$ of its fall to the ground. The height of the minaret in meters is (take $g = 10 \ m/s^2$):

Ball-$1$ is dropped from the top of a building from rest. At the same moment, ball-$2$ is thrown upward towards ball-$1$ with a speed $14 \,m/s$ from a point $21 \,m$ below the top of the building. How far will ball-$1$ have dropped when it passes ball-$2$? (Assume acceleration due to gravity, $g=10 \,m/s^2$.)

Discuss the observation of Galileo for objects falling freely.