A force of $98\, N$ is required to just start moving a body of mass $100\, kg$ over ice. The coefficient of static friction is
$0.6$
$0.4$
$0.2$
$0.1$
A uniform chain of length $L$ which hanges partially from a table, is kept in equilibrium by friction. The maximum length that can withstand without slipping is $l$ , then coefficient of friction between the table and the chain is
A rectangular box lies on a rough inclined surface. The coefficient of friction between the surface and the box is $\mu $. Let the mass of the box be $m$.
$(a)$ At what angle of inclination $\theta $ of the plane to the horizontal will the box just start to slide down the plane ?
$(b)$ What is the force acting on the box down the plane, if the angle of inclination of the plane is increased to $\alpha > \theta $ ?
$(c)$ What is the force needed to be applied upwards along the plane to make the box either remain stationary or just move up with uniform speed ?
$d)$ What is the force needed to be applied upwards along the plane to make the box move up the plane with acceleration $a$ ?
Impending relative motion is opposed by which type of friction ?
A block of mass $2 kg$ slides down an incline plane of inclination $30^o$. The coefficient of friction between block and plane is $0.5$. The contact force between block and plank is :
Among the forces in nature, friction can be classified into