If the mass of the rope ${\mathrm{OO}}^{\text{'}}$ is $M,$ then tension at mid-point $A$ is

A $3 \mathrm{kg}$ block is resting on a truck moving with acceleration $2 \mathrm{m} {\mathrm{s}}^{-2}$ on a horizontal road. Force of friction on the block is

A body is moving on a circular track of radius $R$ at constant speed as shown in figure. If normal reaction at $C$ is $N,$ then

Tension in string $BC$ is (if string and pulley are massless)

Three blocks of masses $2 \mathrm{kg}, 3 \mathrm{kg}$ and $5 \mathrm{kg}$ are connected with massless string and placed on frictionless surface. If system is pulled by force $F,$ then the ratio of $T_1$ and $T_2$ is