If the kinetic energy of a particle continuously increases with time then?

A man applying a force $F$ upon a stretched spring is stationary in a compartment moving with constant speed $v$. The compartment covers a distance $L$ in some time $t$.

A block of mass $2 \mathrm{kg}$ is hanging over a smooth and light pulley through a light string. The other end of the string is pulled by a constant force $F=40 \mathrm{N}$. At $t=0$ the system is at rest as shown. Then in the time interval $t=0$ to $t=\frac{2}{\sqrt{10}} \mathrm{s}$, pick the correct statement(s). (Take, $g=10 \mathrm{m} {\mathrm{s}}^{-2}$)

A force $F$ (power of $F$ is $p=$ constant) is applied on block $A$ of mass $m$ as shown in the figure, $F$ is parallel to the inclined plane. Then:

Two bodies of mass $m_1$ and $m_2 (m_2>m_1)$ are connected by a light inextensible string which passes through a smooth fixed pulley as shown. Then choose the correct option(s) 

The given plot shows the variation of $U$, the potential energy of interaction between two particles with the distance separating them is $r$. Then which of the following statements is/are correct:

A single conservative force $F\left(x\right)$ acts on a particle that moves along the $x$-axis. The graph of the potential energy with $x$ is given $x=5 \mathrm{m}$, the particle has a kinetic energy of $50 \mathrm{J}$ and its potential energy is related to the position $x$ as $U=15+{\left(x–3\right)}^2 \mathrm{Joule}$, where $x$ is in $\mathrm{meter}$.