Which graph best shows the velocity-time graph for an object launched vertically into the air when air resistance is given by $|D| = bv$? The dashed line shows the velocity graph if there were no air resistance.

Due to the presence of air resistance,if a body dropped from a height of $20 \ m$ reaches the ground with a speed of $18 \ m/s$,then the time taken by the body to reach the ground is nearly (in $s$)

$A$ juggler throws balls vertically upwards with the same initial velocity in the air. When the first ball reaches its highest position,he throws the next ball. Assuming the juggler throws $n$ balls per second,the maximum height the balls can reach is

$A$ particle is thrown vertically upwards. It passes the same height at $t_1 = 2 \; s$ and $t_2 = 10 \; s$. The height is:

$A$ parachutist after bailing out falls $50\, m$ without friction. When the parachute opens,it decelerates at $2\, m/s^2$. He reaches the ground with a speed of $3\, m/s$. At what height did he bail out (in $, m$)?

$A$ cricket ball is thrown up with a speed of $19.6 \ m/s$. The maximum height it can reach is ......... $m$.