The area of the acceleration-displacement curve of a body gives

$A$ bullet of mass $1 \ kg$ fired with a speed $2 \ m \ s^{-1}$ from $x = 0$ passes through a block of wood whose centre is kept at a distance of $10 \ m$ from the origin as shown in figure. The retarding force $F_r$ on the bullet within the wooden block is $-0.5/x$. The minimum length of the block (up to $1$ decimal digit) required to completely stop the bullet is (Assume $e^4 = 55$). (in $m$)

$A$ particle moves along the $x$-axis from $x = 0$ to $x = 10 \ m$ under the influence of a force $\vec{F}(x) = (3x^2 - 2x + 7) \hat{i} \ N$. The work done during this displacement is ........ $J$.

$A$ particle is moved along a path $A-B-C-D-E-F-A$,as shown in the figure,in the presence of a force $\vec{F} = (\alpha y \hat{i} + 2 \alpha x \hat{j}) \ N$,where $x$ and $y$ are in meters and $\alpha = -1 \ N/m$. The work done on the particle by this force $\vec{F}$ will be . . . . . . Joule.

$A$ force $F = 20 + 10y$ acts on a particle in the $y$ direction,where $F$ is in newton $(N)$ and $y$ is in meter $(m)$. The work done by this force to move the particle from $y = 0$ to $y = 1 \; m$ is ...... $J$.

$A$ force of $F=(5 y+20) \hat{j} \, N$ acts on a particle. The work done by this force when the particle is moved from $y=0 \, m$ to $y=10 \, m$ is $... \, J.$