Question

With increase of temperature, the frictional force acting between two surfaces ....................... .

• A. increases
• B. decreases
• C. remains constant
• D. None

Answer 1

The correct option is B decreases

Friction between two surfaces changes as the temperature changes. When the temperature rises the thermal movement ability of the moving units improves and due to thermal expansion the space between molecules increases and so the speed of the molecules increases. Due to the the physical quantities changes which affects the frictional force between two surfaces. Also the kinetic co-efficient between surfaces increases which leads to decrease in temperature.

However these changes in frictional force is different for different types of surfaces.