$A$ mass $M$ is placed on a smooth wedge of angle $\theta$ resting on a frictionless surface. To keep the mass $M$ at rest relative to the wedge,the wedge must be given a horizontal acceleration $a$ equal to:

$A$ box of mass $m \, kg$ is placed on the rear side of an open truck accelerating at $4 \, m/s^2$. The coefficient of friction between the box and the surface below it is $0.4$. The net acceleration of the box with respect to the truck is zero. The value of $m$ is $[g = 10 \, m/s^2]$.

$A$ wire is bent into the shape of a parabola given by $Y = Kx^2$. $A$ bead of mass $m$ is placed on the wire,which can slide on it without friction. Initially,when the wire is at rest,the bead is at the lowest point of the parabola. If the wire is now moved with a constant acceleration $a$ parallel to the $X$-axis,what will be the distance of the new equilibrium position of the bead from the $Y$-axis,such that it remains stationary relative to the wire?

The horizontal acceleration that should be given to a smooth inclined plane of angle $\theta = \sin^{-1}\left(\frac{1}{l}\right)$ to keep an object stationary on the plane,relative to the inclined plane is:

$A$ vessel containing water is moving with a constant speed towards the right along a straight horizontal path. If the vessel is given a constant retardation towards the right along a straight line,which of the following diagrams represents the surface of the liquid?

$A$ body of mass $1.0 \, kg$ is falling with an acceleration of $10 \, m/s^2$. Its apparent weight will be ......... $kg \, wt$ $(g = 10 \, m/s^2)$.