Factors affecting friction

Q.

A cube is pushed in such a way that it is sliding on a horizontal surface. Frictional force acting on the cube can be increased by:

1. Adding wheels to the cube.

2. Applying lubricant between the cube and the surface.

3. Polishing the outer surface of the cube.

4. Placing another identical cube on top of the cube.

Q.

Neha has to push a light box and Sohit has to push a comparatively heavier box made of same material, on the same horizontal floor. What can we say about the forces applied by them?

1. It rubs against the ice

2. It runs out of electricity

3. Force of gravity made it slow

4. It runs out of push

Q. Friction depends on the following two factors:
(a) Materials of the body in ___.
(b) ___ of the two surfaces.

1. contact:roughness
2. air:density
3. fluids:volume
4. vacuum:mass

Q.

Friction can act between two bodies even when they are not in contact.

1. True

2. False