A football of radius $R$ is kept on a hole of radius $r (r < R)$ made on a plank kept horizontally. One end of the plank is now lifted so that it gets tilted making an angle $\theta$ from the horizontal as shown in the figure below. The maximum value of $\theta$ so that the football does not start rolling down the plank satisfies (figure is schematic and not drawn to scale) -
$\sin \theta=\frac{r}{R}$
$\tan \theta=\frac{r}{R}$
$\sin \theta=\frac{r}{2 R}$
$\cos \theta=\frac{r}{2 R}$
A block of $\sqrt{3}\,kg$ is attached to a string whose other end is attached to the wall. An unknown force $F$ is applied so that the string makes an angle of $30^{\circ}$ with the wall. The tension $T$ is $...........\,N$ :(Given $g =10\,ms ^{-2}$ )
Two equal heavy spheres, each of radius $r$, are in equilibrium within a smooth cup of radius $3 r$. The ratio of reaction between the cup and one sphere and that between the two sphere is
A man is pulling on a rope attached to a block on a smooth horizontal table. The tension in the rope will be the same at all points
A uniform rope of mass $M$ and length $L$ is fixed at its upper end vertically from a rigid support. Then the tension in the rope at the distance $l$ from the rigid support is $x$