Following figures show two different systems in equilibrium. The spring balance reads the tension in the string. There is no friction anywhere and pulleys are light. Select the correct alternative. ($S_1, S_2, S_3$ and $S_4$ are the readings of the balances)

 

In the arrangement shown, the pulleys are massless and frictionless. The rope connected to the block is also light and inextensible. The system is in equilibrium. Select the correct alternative.

A block of mass $m$ is connected with another block of mass $2m$ by a light spring. $2m$ is connected with a hanging mass $3m$ by an inextensible light string. At the time of release of block $3m$

The two arrangement of identical frictionless and massless pulleys, string and blocks are shown in figure (a) and figure (b). Which of the following statement(s) is/are correct?

A small block of mass $m$ is placed at one end of a plank of mass $M$ and length $l.$ A force $F$ is applied at the other end as shown in figure. If there is no friction at any contact surfaces, then

In the figure, the pulley $P$ moves to the right with a constant speed $u$. The downward speed of $A$ is $v_{\mathrm{A}}$ and the speed of $B$ to the right is $v_{\mathrm{B}}$.

Pulleys and threads shown in the figure are ideal

A block of mass $m$ slides down a rough inclined plane with an acceleration $\frac{g}{2}$

At $t=0,$ a small body is projected with a velocity of $30 \mathrm{m} {\mathrm{s}}^{–1},$ on a rough horizontal surface. The coefficient of friction $\left(\mu \right)$ between the surfaces, changes with time $t$ as the body moves along the surface through different points as shown in graph $\left(g=10 \mathrm{m} {\mathrm{s}}^{–2}\right).$ Select the correct alternative.