$A$ block of mass $10\,kg$ is moving along the $x$-axis under the action of a force $F = 5x\,N$. The work done by the force in moving the block from $x = 2\,m$ to $4\,m$ will be ............$J$.

$A$ body covers a distance of $2\,m$ under the influence of a force $F = 15 - 4x\,N$,where $x$ is the distance covered by the particle in meters. The work done by the force is ............ $J$.

$A$ particle moves in one dimension from rest under the influence of a force that varies with the distance traveled by the particle as shown in the figure. The kinetic energy of the particle after it has traveled $3\, m$ is ................ $J$.

$A$ force is applied to a particle of mass $0.1 \ kg$ as a function of distance as shown in the figure. If it starts from rest at $x = 0$,its velocity at $x = 12 \ m$ is ....... $m/s$.

$A$ force $\vec{F} = (-6x^3 \hat{i}) \ N$ acts on a particle,causing a displacement from $x = 4 \ m$ to $x = -2 \ m$. The work done by the force is .......... $J$.

What is a variable force? Write the equation for the work done by a variable force in one dimension.