$A$ person standing on the floor of an elevator drops a coin. The coin reaches the floor in time $t_{1}$ if the elevator is at rest and in time $t_{2}$ if the elevator is moving uniformly. Then

$A$ stone is thrown with an initial speed of $4.9 \, m/s$ from a bridge in a vertically upward direction. It falls down into the water after $2 \, s$. The height of the bridge is .......... $m$.

$A$ man throws a ball vertically upward and it rises to a height of $20 \; m$ before returning to his hands. What was the initial velocity $(u)$ of the ball and for how much time $(T)$ did it remain in the air? $[g = 10 \; m/s^2]$

$A$ ball is thrown upwards from the top of a tower $40\,m$ high with a velocity of $10\,m/s$. Find the time when it strikes the ground (in seconds). Take $g = 10\,m/s^2$.

$A$ body is dropped from a height $h$. If it acquires a momentum $p$ just before striking the ground,then the mass of the body is

$A$ player throws a ball upwards with an initial speed of $29.4\; m s^{-1}$. Choose the $x=0\; m$ and $t=0\; s$ to be the location and time of the ball at its highest point. Let the vertically downward direction be the positive direction of the $x$-axis. Determine the signs of position,velocity,and acceleration of the ball during its upward and downward motion.