A particle is projected vertically upwards with a speed of $16\  m/s$ , after some time , when it again passes through the point of projection, its speed is found to be $8\  m/s$ . It is known that the work done by air resistance is same during upward and downward motion. Then the maximum height attained by the particle is ...................... $\mathrm{m}$ ( $g$ = $10\  m/s^2$ )

$A$ box of mass $m$ is released from rest at position $1$ on the frictionless curved track shown. It slides a distance $d$ along the track in time $t$ to reach position $2$, dropping a vertical distance $h$. Let $v$ and $a$ be the instantaneous speed and instantaneous acceleration, respectively, of the box at position $2$. Which of the following equations is valid for this situation?

A particle of mass $500 \,gm$ is moving in a straight line with velocity $v=b x^{5 / 2}$. The work done by the net force during its displacement from $x=0$ to $x =4 \,m$ is ...................$J$ (Take $b =0.25 \,m ^{-3 / 2} s ^{-1}$ )

A body of mass $1\,kg$ is thrown upwards with a velocity $20\, m/s.$ It momentarily comes to rest after attaining a height of $18\, m.$ How much energy is lost due to air friction ? ........... $\mathrm{J}$ $ (g = 10 \,m/s^2)$

Consider an elliptically shaped rail $P Q$ in the vertical plane with $O P=3 \ m$ and $OQ =4 \ m$. A block of mass $1 \ kg$ is pulled along the rail from $P$ to $Q$ with a force of $18 \ N$, Which is always parallel to line $PQ$ (see the figure given). Assuming no frictional losses, the kinetic energy of the block when it reaches $Q$ is $(n \times 10)$ joules. The value of $n$ is (take acceleration due to gravity $=10 \ ms ^{-2}$ )

A block of mass $2\, kg$ is placed on a rough inclined plane as shown in the figure $(\mu = 0.2)$ so that it just touches the spring. The block is allowed to move downwards. The  spring will be compressed to a maximum of .............. $\mathrm{cm}$