Question

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:

• A. Adding wheels to the cube.
• B. Applying lubricant between the cube and the surface.
• C. Polishing the outer surface of the cube.
• D. Placing another identical cube on top of the cube.

Answer 1

The correct option is D

Placing another identical cube on top of the cube.

Adding wheels to the cube or polishing its surface will reduce the friction. Applying lubricant between the cube and the surface will also have a similar effect. But when another cube is placed on top of the existing cube, the effective weight of the cube increases. This increases the frictional force acting on the cube as frictional force increases with increase in weight.