What two factors affect the force of friction?

Weight of the object and size

Mass of the object and velocity

Roughness of the surface and weight of the object

Velocity and roughness of surface

Answer : Option C) Roughness of the surface and weight of the object.

Explanation : The factors that affect the forces of friction are roughness of the surface and weight of the object.

Friction is the force which resists the relative motion of solid surfaces, fluid layers, and material elements which are sliding against each other.

Friction depends on the normal force and the roughness of the surface which is in contact. When a body is placed on the ground, the mass of the body which is weight = mass x acceleration due to gravity, comes into play for the normal force from the ground. This clearly shows that friction is affected by weight as it depends on the mass of the object.

It also depends partly on the smoothness of the contacting surfaces, if a greater force being applied to move two surfaces past one another then they are rough, if they were smooth less force would have been applied for moving it.

Roughness of the surface and weight of the object.