......... $m/s^2$ is magnitude of acceleration of a block moving with speed $10\,m/s$ on a rough surface if coefficient of friction is $0.2$.

The coefficient of friction $\mu $ and the angle of friction $\lambda $ are related as

A rope of length $L$ and mass $M$ is being pulled on a rough horizontal floor by a constant horizontal force $F$ = $Mg$ . The force is acting at one end of the rope in the same direction as the length of the rope. The coefficient of kinetic friction between rope and floor is $1/2$ . Then, the tension at the midpoint of the rope is

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 :

A football player is moving southward and suddenly turns eastward with the same speed to avoid an opponent. The force that acts on the player while turning is :

A block of mass $m$ is moving with a constant acceleration a on a rough plane. If the coefficient of friction between the block and ground is $\mu $, the power delivered by the external agent after a time $t$ from the beginning is equal to