Answer:
4 is gravitational force
Option B
Explanation:
This is a force diagram of a block on an inclined plane.
The force component is what makes up weight in the diagram. Weight is given as mass multiplied by the gravity.
Gravitational force acts downward and it is the force of attraction between all objects and the earth. It is directly proportional to mass.
Force 1 and 2 are both shear forces that acts parallel to the face of the incline. They are mostly expressed as frictional forces.
