$A$ block of mass $m$ is pressed against a vertical wall by a horizontal force of magnitude $mg$. An upward force of magnitude $\frac{mg}{2}$ is also applied to the block. If the block is in equilibrium,the minimum coefficient of friction $\mu$ between the block and the wall is:

$A$ spring-block system is placed on a rough horizontal floor. The block is pulled towards the right to give the spring some elongation and then released. The block will have maximum velocity when:

$A$ conveyor belt is moving horizontally with a velocity of $2 \,m \,s^{-1}$. If a body of mass $10 \,kg$ is kept on it, then the distance travelled by the body before coming to rest relative to the belt is (The coefficient of kinetic friction between the belt and the body is $0.2$ and acceleration due to gravity is $10 \,m \,s^{-2}$) (in $\,m$)

$A$ block of mass $m$ (initially at rest) is sliding up 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 seconds. At $t = 0$,the force is in the vertical upward direction,and as time passes,its direction changes until $\theta = \frac{\pi }{2}$. The value of $F$ such that the block comes to rest when $\theta = \frac{\pi }{2}$ is:

Why are rubber tires preferred over steel tires for vehicle wheels?

Find the work done against friction in $J$ when a block of mass $50\, kg$ moves a distance of $1\, m$ on a rough horizontal surface with a coefficient of friction of $0.2$.