Question

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)

• A. $\sin \theta=\frac{ r }{ R }$
• B. $\tan \theta=\frac{ r }{ R }$
• C. $\sin \theta=\frac{ r }{2 R }$
• D. $\cos \theta=\frac{ r }{2 R }$

Answer 1

Answer: (A)

$\sin \theta=\frac{ r }{ R }$

Answer 2

The Correct Option is (A): $\sin \theta=\frac{ r }{ R }$