When a body is lying on a rough inclined plane and does not move, the force of friction

An insect crawls up a hemispherical surface very slowly. 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 $ so that the insect does not slip is given by

A $60\, kg$ body is pushed with just enough force to start it moving across a floor and the same force continues to act afterwards. The coefficient of static friction and sliding friction are $0.5$ and $0.4$ respectively. The acceleration of the body is  ........ $m/{s^2}$

A particle is moving along the circle $x^2 + y^2 = a^2$ in anti clock wise direction. The $x-y$ plane is a rough horizontal stationary surface. At the point $(a\, cos\theta , a\, sin\theta )$, the unit vector in the direction of friction on the particle is:

A block slides down on incline of angle $30^o$ with an acceleration $\frac{g}{4}$. Find the coefficient of kinetic friction

Which of the following is correct, when a person walks on a rough surface