Question

What are the two factors that affect the frictional force between two surfaces?

Answer 1

Answer:

10m/s²

Explanation:

average acceleration =final velocity-initial velocity/time taken

40-0/4

=40/4

=10m/s²

Ans B

Answer 2

The factors that affect frictional force between two surfaces are following

• Roughness/smoothness of the sliding object and the surface - Smooth body slides over surfaces easily compared to rough ones. These irregularities hinder the sliding between the surfaces. Thus, more the roughness of the body higher is the friction. Similarly, the smoothness of the surface, more is the sliding and less is the friction.
• The force between the two bodies in the normal direction -  The force that surface exerts on the body is in the normal direction. It will increase the interaction between the surface and thus hinder the sliding and so friction force increases. Friction is thus directly proportional to the normal force applied. [f = μ * N, where μ is the coefficient of friction]