$A$ block $P$ of mass m is placed on a frictionless horizontal surface. Another block Q of same mass is kept on $P$ and connected to the wall with the help of a spring of spring constant k as shown in the figure. ${\mu _s}$ is the coefficient of friction between$  P$ and $ Q$. The blocks move together performing SHM of amplitude $A$. The maximum value of the friction force between $P$ and $Q$ is

30-6

  • [IIT 2004]
  • A

    $kA$

  • B

    $\frac{{kA}}{2}$

  • C

    Zero

  • D

    ${\mu _s}\,mg$

Similar Questions

A force of $98\, N$ is required to just start moving a body of mass $100\, kg$ over ice. The coefficient of static friction is

A block of mass $m$ rests on a rough inclined plane. The coefficient of friction between  the surface and the block is $\mu$. At what angle of inclination $\theta$ of the plane to  the horizontal will the block just start to slide down the plane?

A circular racetrack of radius $300\; m$ is banked at an angle of $15^o$. If the coefficient of friction between the wheels of a race-car and the road is $0.2$, what is the

$(a)$ optimum speed of the racecar to avoid wear and tear on its tyres, and

$(b)$ maximum permissible speed to avoid slipping ?

A block pressed against the vertical wall is in equilibrium. The minimum coefficient of  friction is:-

A block of wood resting on an inclined plane of angle $30^o$, just starts moving down. If the coefficient of friction is $0.2$, its velocity (in $ms^{-1}$) after $5\, seconds$ is : $(g = 10\, ms^{-2})$