question_answer

An insect crawls up a hemispherical surface very slowly (see the figure). The coefficient of friction between the insect and the surface is 1/3. If the line joining the centre of the hemispherical surface to the insect makes an angle \[\alpha \]with the vertical, the maximum possible value of \[\alpha \] is given by                                              [IIT-JEE 2001]

A) \[\cot \alpha =3\]

B)    \[\tan \alpha =3\]

C) \[\sec \alpha =3\]

D)    \[\text{cosec}\,\alpha =\text{3}\]