Question

A 16kg mass is put on a 30° frictionless inclined plane and is attached to a pulley that is connected to a 5kg hanging mass. What should the mass of the object in the inclined plane be in order for the system to attain static equilibrium?

Answer 1

The condition for static equilibrium:

$$mg=Mg\sin\theta,\\\space\\ M=m/\sin\theta=5/0.5=10\text{ kg}.$$