A body of mass $10\,kg$ is moving with an initial speed of $20\,m / s$. The body stops after $5\,s$ due to friction between body and the floor. The value of the coefficient of friction is (Take acceleration due to gravity $g =10\; ms ^{-2}$)

It is easier to roll a barrel than pull it along the road. This statement is

It is difficult to move a cycle with brakes on because

A heavy box is solid across a rough floor with an initial speed of $4 \,m / s$. It stops moving after $8$ seconds. If the average resisting force of friction is $10 \,N$, the mass of the box (in $kg$ ) is .....

Two bodies $A$ and $B$ of masses $5 kg$ and $10 kg$ in contact with each other rest on a table against a rigid wall. The coefficient of friction between the bodies and the table is $0.15$. A force of 200 $N$ is applied hortzontally to $A$. What are $(a)$ the reaction of the partition $(b)$ the action-reaction forces between $A$ and $B ?$ What happens when the wall is removed? Does the answer to $(b)$ change, when the bodies are in motion? Ignore the difference between $\mu_{ s }$ and $\mu_{ k }$

A block of mass $10 kg$ is moving on a rough surface as shown in figure. The frictional force acting on block is ...... $N$