A block of mass $m_1=1 \ kg$ another mass $m_2=2 \ kg$, are placed together (see figure) on an inclined plane with angle of inclination $\theta$. Various values of $\theta$ are given in List $I$. The coefficient of friction between the block $m _1$ and the plane is always zero. The coefficient of static and dynamic friction between the block $m _2$ and the plane are equal to $\mu=0.3$. In List $II$ expression for the friction on block $m _2$ given. Match the correct expression of the friction in List $II$ with the angles given in List $I$, and choose the correct option. The acceleration due to gravity is denoted by $g$.
[Useful information : $\tan \left(5.5^{\circ}\right) \approx 0.1 ; \tan \left(11.5^{\circ}\right) \approx 0.2 ; \tan \left(16.5^{\circ} \approx 0.3\right)$ ]
List $I$ | List $II$ |
$P.\quad$ $\theta=5^{\circ}$ | $1.\quad$ $m _2 g \sin \theta$ |
$Q.\quad$ $\theta=10^{\circ}$ | $2.\quad$ $\left(m_1+m_2\right) g \sin \theta$ |
$R.\quad$ $\theta=15^{\circ}$ | $3.\quad$ $\mu m _2 g \cos \theta$ |
$S.\quad$ $\theta=20^{\circ}$ | $4.\quad$ $\mu\left(m_1+m_2\right) g \cos \theta$ |
$P-1, Q-1, R-1,S-3$
$P-2, Q-2, R-2,S-3$
$P-2, Q-2, R-2,S-4$
$P-2, Q-2, R-3,S-3$
A block of mass $m$ is placed on a smooth inclined wedge $ABC$ of inclination $\theta$ as shown in the figure. The wedge is given an acceleration $a$ towards the right. The relation between $a$ and $\theta$ for the block to remain stationary on the wedge is
Two blocks of mass $M_1 = 20\,kg$ and $M_2 = 12\,kg$ are connected by a metal rod of mass $8\,kg.$ The system is pulled vertically up by applying a force of $480\,N$ as shown. The tension at the mid-point of the rod is ........ $N$
Three identical blocks of masses $m=2\; k g$ are drawn by a force $F=10.2\; N$ with an acceleration of $0.6\; ms ^{-2}$ on a frictionless surface, then what is the tension (in $N$) in the string between the blocks $B$ and $C$?
Three blocks are placed as shown in figure. Mass of $A, B$ and $C$ are $m_1, m_2$ and $m_3$ respectively. The force exerted by block ' $C$ ' on ' $B$ ' is .........