Question

Friction can be increased by:

• A. Making grooves and treads on the surface.
• B. Streamlining the object.
• C. Lubricating the two surfaces in contact.
• D. All of the above.

Answer 1

The correct option is A

Making grooves and treads on the surface.

The explanation for the correct answer:

Option (A): Making grooves and treads on the surface.

1. The frictional force is a contact force that acts between two surfaces in contact.
2. At microscopic levels, even a smooth-looking surface has irregularities that cause friction.
3. Making grooves and treads on the surface will increase the irregularities which will increase frictional force.
4. For example, groves are created on tires to increase friction between vehicle and road.

The explanation for the incorrect answer:

1. Option B: Streamlining objects like boats, airplanes, and sports cars can easily cut through the water or air hence opposing force or frictional force will reduce.
2. Option C: Lubricant will form a thin layer between two surfaces smoothening the irregularities which will reduce frictional force.

Hence the right answer is option A.