Two blocks $A$ and $B$ of masses 2 kg and 4 kg respectively are kept on a rough horizontal surface. If same force of 20 N is applied on each block, then the ratio of the accelerations of the blocks $A$ and $B$ is (Coefficient of kinetic friction between the surface and the blocks is 0.3 and acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )

If the tension in the horizontal wire shown in the figure is 30 N , then the weight $W$ and tension in the wire $O A$ are respectively

A balloon with mass ' $m$ ' is descending vertically with an acceleration ' $a$ ' (where $a

A conveyor belt is moving horizontally with a velocity of $2 \mathrm{~ms}^{-1}$. If a body of mass 10 kg is kept on it, then the distance travelled by the body before coming to rest is

(The coefficient of kinetic friction between the belt and the body is 0.2 and acceleration due to gravity is $10 \mathrm{~ms}^{-2}$ )