A marble block of mass $2\, kg$ lying on ice when given a velocity of $6\, m/s$ is stopped by friction in $10s$. Then the coefficient of friction is-

An army vehicle of mass $1000\, kg$ is moving with a velocity of $10 \,m/s$ and is acted upon by a forward force of $1000\, N$ due to the engine and a retarding force of $500 \,N$ due to friction. ........... $m/s$ will be its velocity after $10\, s$

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 hockey player is moving northward and suddenly turns westward with the same speed to avoid an oopponent. The force that acts on the player is

A uniform rod of length $L$ and mass $M$ has been placed on a rough horizontal surface. The horizontal force $F$ applied on the rod is such that the rod is just in the state of rest. If the coefficient of friction varies according to the relation $\mu = Kx$ where $K$ is a $+$ ve constant. Then the tension at mid point of rod is

A block of mass $m$ is stationary on a rough plane of mass $M$ inclined at an angle $\theta$ to the horizontal, while the whole set up is accelerating upwards at an acceleration $\alpha$. If the coefficient of friction between the block and the plane is $\mu$, then the force that the plane exerts on the block is