In the figure,a block of weight $60 \ N$ is placed on a rough surface. The coefficient of friction between the block and the surface is $0.5$. What should be the maximum weight $W$ (in $N$) such that the block does not slip on the surface?

$A$ $20 \text{ ton}$ truck is travelling along a curved path of radius $240 \text{ m}$. If the center of gravity of the truck above the ground is $2 \text{ m}$ and the distance between its wheels is $1.5 \text{ m}$, the maximum speed of the truck with which it can travel without toppling over is (Acceleration due to gravity $= 10 \text{ ms}^{-2}$) (in $\text{ ms}^{-1}$)

Two blocks,$4\, kg$ and $2\, kg$,are sliding down an inclined plane as shown in the figure. The acceleration of the $2\, kg$ block is ........ $m/s^2$.

An electric lift with a maximum load of $2000\,kg$ (lift + passengers) is moving up with a constant speed of $1.5\,m/s$. The frictional force opposing the motion is $3000\,N$. The minimum power delivered by the motor to the lift in watts is: $(g=10\,m/s^2)$

For the given system,find the tension $T_2$ in the upper string.

$A$ spring-block system is placed on a rough horizontal floor. The block is pulled towards the right to give the spring some elongation and then released.