Two masses M1 and M2 are attached to the ends of a string which passes over a pulley attached to the top of an inclined plane. The angle of inclination of the plane is θ. Take g = 10 ms⁻²

The correct option is Zero.

Let us analyze the system consisting of two masses:

$M_1$

and

$M_2$

connected by a string passing over a pulley at the top of an inclined plane of angle

$\theta$

If mass $M_1$ is placed on the inclined plane and mass $M_2$ hangs vertically, the forces acting along the string are the component of gravitational force down the incline and the weight of the hanging mass.

When these forces balance each other, the system is in static equilibrium:

$M_{1}gsin\theta =M_{2}g$

Since the net force acting on the system is zero, the acceleration of the masses is also zero:

$a=0{\text{ms}}^{-2}$

Hence, the acceleration of the system is Zero.