Two masses of $8\,kg$ and $4\,kg$ are connected by a string as shown in the figure over a frictionless pulley. The acceleration of the system is ............ $m/s^2$.

$A$ double inclined plane as shown in the figure has a fixed horizontal base and smooth faces with the same angle of inclination of $30^{\circ}$. $A$ block of mass $m_2 = 300 \ g$ is on one face and is connected by a cord passing over a frictionless pulley to a second block of mass $m_1 = 200 \ g$ kept on the other face. The acceleration with which the system of the blocks moves is ........ $\%$ of acceleration due to gravity $(g)$.

If $M_1 = M_2 = 5 \, kg$ and $\theta = 30^\circ$,then the tension in the string will be ........... $N$.

$A$ block of mass $m$ is released from rest at point $A$ on an inclined plane of angle $\theta$ with the vertical. The block slides down and compresses a spring of spring constant $k$. Find the compression in the spring when the speed of the block is maximum.

The time taken by a block of wood (initially at rest) to slide down a smooth inclined plane $9.8 \ m$ long (angle of inclination is $30^o$) is ......... $sec$.

$A$ body of mass $1\, kg$ lies on a smooth inclined plane. The body is subjected to a horizontal force $F = 10\, N$ as shown in the figure. The magnitude of the net normal reaction on the body is: