$A$ block of mass $m$ starts from rest and slides down a frictionless semi-circular track from a height $h$ as shown. When it reaches the lowest point of the track,it collides with a stationary piece of putty also having mass $m$. If the block and the putty stick together and continue to slide,the maximum height that the block-putty system could reach is:

$A$ ball is projected vertically upwards. Air resistance and variation in $g$ may be neglected. The ball rises to its maximum height $H$ in a time $T$,the height being $h$ after a time $t$.
[$1$] The graph of kinetic energy $E_k$ of the ball against height $h$ is shown in figure $1$.
[$2$] The graph of height $h$ against time $t$ is shown in figure $2$.
[$3$] The graph of gravitational potential energy $E_g$ of the ball against height $h$ is shown in figure $3$.
Which of the following shows the correct answers?

Three particles $A, B$,and $C$ of equal mass move with speed $V$ as shown to strike at the centroid of an equilateral triangle. After the collision,$A$ comes to rest and $B$ retraces its path with speed $V$. The speed of $C$ after the collision is:

$300 \, J$ of work is done in sliding up a $2 \, kg$ block on an inclined plane to a height of $10 \, m$. Taking the value of acceleration due to gravity $g$ to be $10 \, m/s^2$,the work done against friction is ........ $J$.

Two objects having masses in the ratio $1:4$ are at rest. When both of them are subjected to the same force separately,they achieve the same kinetic energy during times $t_1$ and $t_2$ respectively. Then the ratio of $t_1$ to $t_2$ is

$A$ block of mass $0.18 \ kg$ is attached to a spring of force constant $2 \ N/m$. The coefficient of friction between the block and the floor is $0.1$. Initially,the block is at rest and the spring is unstretched. The block is pushed as shown in the figure. The block slides a distance of $0.06 \ m$ and comes to rest. If the initial velocity of the block is $V = N/10 \ m/s$,then what is the value of $N$?