$A$ weight $W$ can be just supported on a rough inclined plane by a force $F$ either acting along the plane or horizontally. If $\theta$ is the angle of friction,then $F / W$ is

$A$ block is at rest on an inclined plane making an angle $\alpha$ with the horizontal. As the angle $\alpha$ of the incline is increased,the block starts slipping when the angle of inclination becomes $\theta$. The coefficient of static friction between the block and the surface of the inclined plane is:

The time taken by an object to slide down a $45^{\circ}$ rough inclined plane is $n$ times the time it takes to slide down a perfectly smooth $45^{\circ}$ inclined plane. The coefficient of kinetic friction between the object and the inclined plane is:

Two blocks $A$ and $B$ are released from the top of a rough inclined plane so that $A$ slides along the plane and $B$ falls down freely. Which will have higher velocity on reaching the ground?

When a body is placed on a rough plane inclined at an angle $\theta$ to the horizontal,its acceleration is

$A$ box when dropped from a certain height reaches the ground with a speed $v$. When it slides from rest from the same height down a rough inclined plane inclined at an angle $45^{\circ}$ to the horizontal,it reaches the ground with a speed $v/3$. The coefficient of sliding friction between the box and the plane is: