Question

What causes friction between two surfaces in contact when they try to slide past each other?

• A. Interlocking of irregularities present on the surfaces
• B. Rigidity of the surfaces
• C. Gravitational attraction between the surfaces
• D. Presence of atmosphere around the surfaces

Answer 1

Answer: (A)

Interlocking of irregularities present on the surfaces

Friction is caused by interlocking of irregularities present on the surfaces in contact. Rough surfaces have larger irregularities while smoother surfaces have lesser irregularities. Hence, rough surfaces offer more friction as compared to smooth surfaces. Even surfaces that appear smooth have numerous minute irregularities present on them.