$A$ body falls freely for $10 \ s$. What is its average velocity during this journey (in $m/s$)? (Take $g = 10 \ m/s^2$)

$A$ 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 $g = 10\,m/s^2$.

$A$ ball is projected vertically up from the ground. Boy $A$,standing at the window of the first floor of a nearby building,observes that the time interval between the ball crossing him while going up and the ball crossing him while going down is $2 \ s$. Another boy $B$,standing on the second floor,notices the time interval between the ball passing him twice,during up and down motion,is $1 \ s$. Calculate the difference between the vertical positions of boy $B$ and boy $A$. (Assume $g = 10 \ m \ s^{-2}$) (in $m$)

The initial and final velocities of a body projected vertically from the ground are $20 \,ms^{-1}$ and $18 \,ms^{-1}$ respectively. The maximum height reached by the body is (Acceleration due to gravity $= 10 \,ms^{-2}$) (in $\,m$)

$A$ ball (initially at rest) is released from the top of a tower. The ratio of work done by the force of gravity,in the first,second,and third seconds is

$A$ packet is dropped from a balloon which is going upwards with a velocity of $12 \, m/s$. The velocity of the packet after $2 \, s$ will be ........ $m/s$.