A fireman of mass $60\, kg$ slides down a pole. He is pressing the pole with a force of $600 \,N$. The coefficient of friction between the hands and the pole is $0.5$, with what acceleration will the fireman slide down ........ $m/s^2$
$1$
$2.5$
$10$
$5$
A block of mass $40 \,kg$ slides over a surface, when a mass of $4 \,kg$ is suspended through an inextensible massless string passing over frictionless pulley as shown below. The coefficient of kinetic friction between the surface and block is $0.02$. The acceleration of block is ............ $ms ^{-2}$ (Given $g =10 \,ms ^{-2}$.)
The limiting friction is
A block of weight $W$ rests on a horizontal floor with coefficient of static friction $\mu .$ It is desired to make the block move by applying minimum amount of force. The angle $\theta $ from the horizontal at which the force should be applied and magnitude of the force $F$ are respectively.
For a given mass rolling friction is how many times static friction and kinetic friction?