A block of mass $m$ is pressed against a vertical surface by a spring of unstretched length $l$ . If the coefficient of friction between the block and the surface is $\mu $. Choose the correct statement.
Medium
Download our app for free and get startedPlay store
For equilibrium $:-$ $\quad \mathrm{f} \geq \mathrm{mg}$

$\mu \mathrm{Kd} \geq \mathrm{mg} \quad \mathrm{K} \geq \frac{\mathrm{mg}}{\mu \mathrm{d}}$

Hence                  $\mathrm{K}_{\min }=\frac{\mathrm{mg}}{\mu \mathrm{d}}$

art

Download our app
and get started for free

Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*

Similar Questions

  • 1
    A block of mass $m$ is placed on a surface with a vertical cross section given by $y = \frac{{{x^3}}}{6}$ If the coefficient of friction is $0.5$,the maximum height above the ground at which the block can be placed without slipping is:
    View Solution
  • 2
    On a railway curve, the outside rail is laid higher than the inside one so that resultant force exerted on the wheels of the rail car by the tops of the rails will
    View Solution
  • 3
    A block kept on a rough inclined plane, as shown in the figure, remains at rest upto a maximum force $2\,N$ down the inclined plane. The maximum external force up the inclined plane that does not move the block is $10\,N.$ The coefficient of static friction between the block and the plane is : [Take $g = 10\,m/s^2$ ]
    View Solution
  • 4
    A small body slips, subject to the force of friction, from point $A$ to point $B$ along two curved surfaces of equal radius, first along route $1,$ then along route $2$. Friction does not depend on the speed and the coefficient of friction on both routes is the same. In which case will the body’s speed at $B$ be greater?
    View Solution
  • 5
    A mass of $2 \,kg$ is whirled in a horizontal circle by means of a string at an initial speed of $5$ revolutions per minute. Keeping the radius constant the tension in the string is doubled. The new speed is nearly ....... $rpm$
    View Solution
  • 6
    A block $A$ of mass $4\, kg$ is placed on another block $B$ of mass $5\, kg$, and the block $B$ rests on a smooth horizontal table. If the minimum force that can be applied on $A$ so that both the blocks move together is $12\, N$, the maximum force that can be applied to $B$ for the blocks to move together will be $..... N$
    View Solution
  • 7
    The minimum force required to start pushing a body up a rough (frictional coefficient $\mu$) inclined plane is $F _{1}$ while the minimum force needed to prevent it from sliding down is $F _{2}$. If the inclined plane makes an angle $\theta$ from the horizontal such that $\tan \theta=2 \mu$, then the ratio $\frac{F_{1}}{F_{2}}$ is
    View Solution
  • 8
    Acceleration of block $A$ varies with time as shown in figure the value of coefficient of kinetic friction between block $A$ and $B$ is the value of coefficient of kinetic friction between block $A$ and $B$ is .............. 
    View Solution
  • 9
    A block of mass $m$ slides down the plane inclined at angle $30^{\circ}$ with an acceleration $\frac{ g }{4}$. The value of coefficient of kinetic friction will be :
    View Solution
  • 10
    The retarding acceleration of $7.35\, ms^{-2}$ due to frictional force stops the car of mass $400\, kg$ travelling on a road. The coefficient of friction between the tyre of the car and the road is
    View Solution