A block of mass $m$ (initially at rest) is sliding up (in vertical direction) against a rough vertical wall with the help of a force $F$ whose magnitude is constant but direction is changing. $\theta = {\theta _0}t$ where $t$ is time in sec. At $t$ = $0$ , the force is in vertical upward direction and then as time passes its direction is getting along normal, i.e., $\theta = \frac{\pi }{2}$ .The value of $F$ so that the block comes to rest when $\theta = \frac{\pi }{2}$ , is
$\frac{{mg \times \pi }}{{2{\theta _o}}}$
$\frac{{mg \times \pi }}{{2\left( {1 - \mu } \right){\theta _o}}}$
$\frac{{mg \times \pi }}{{\left( {1 - \mu } \right)}}$
$\frac{{mg \times \pi }}{{2\left( {1 - \mu } \right)}}$
Pulling force making an angle $\theta $ to the horizontal is applied on a block of weight $W$ placed on a horizontal table. If the angle of friction is $\alpha $, then the magnitude of force required to move the body is equal to
Two blocks $A$ and $B$ are released from the top of a rough inclined plane so that $A$ slides along the plane and $B$ falls down freely. Which will have higher velocity on reaching the ground ?
If mass of $A = 10\,\,kg$, coefficient of static friction $= 0.2$, coefficient of kinetic friction = $0.2$. Then mass of $B$ to start motion is
A $2\,kg$ block slides on a horizontal floor with a speed of $4\, m/s$. It strikes a uncompressed spring, and compresses it till the block is motionless. The kinetic friction force is $110\,N$ and spring constant is $1000\, N/m$. The spring compresses by ........ $cm$
$A$ 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