$A$ force $F = 10t$ acts on a block of mass $10 \, kg$ as shown in the figure. Find the time $t$ when the block loses contact with the surface.

$A$ rope of length $L$ and mass $M$ is pulled by a constant force $F$ on a frictionless surface. What is the tension in the rope at a distance $x$ from the end where the force is applied?

The minimum acceleration with which a fireman can slide down a rope of breaking strength two-third of his weight is

Three solids of masses $m_1, m_2$ and $m_3$ are connected with weightless strings in succession and are placed on a frictionless table. If the mass $m_3$ is dragged with a force $T$,the tension in the string between $m_2$ and $m_3$ is

$A$ bar of mass $m$ resting on a smooth horizontal plane starts moving due to a constant force $F$. In the process of its rectilinear motion,the angle $\theta$ between the direction of this force and the horizontal varies as $\theta = k x$,where $k$ is a constant and $x$ is the distance traversed by the bar from its initial position. The velocity $(v)$ of the bar as a function of the angle $\theta$ is

The maximum tension a rope can withstand is $60 \,kg$-wt. The ratio of maximum acceleration with which two boys of masses $20 \,kg$ and $30 \,kg$ can climb up the rope at the same time is