A $20\, kg$ block is initially at rest on a rough horizontal surface. A horizontal force of $75 \,N$ is required to set the block in motion. After it is in motion, a horizontal force of $60\, N$ is required to keep the block moving with constant speed. The coefficient of static friction is
$0.38$
$0.44$
$0.52$
$0.6$
In the figure, a block of weight $60\, N$ is placed on a rough surface. The coefficient of friction between the block and the surfaces is $0.5$. ........ $N$ should be the maximum weight $W$ such that the block does not slip on the surface .
What is the maximum value of the force $F$ such that the block shown in the arrangement does not move ....... $N$
Among the forces in nature, friction can be classified into
Determine the maximum acceleration in $m/s^2$ of the train in which a box lying on its floor will remain stationary, given that the co-efficient of static friction between the box and the train’s floor is $0.15.$