Question

Imagine that an object is falling through a long straight glass tube held vertical; the air has been removed completely from the tube. The object does not touch the walls of the tube. Will the object experience any force of friction?

Answer 1

Explanation

1. Friction is caused due to the irregularities on the two surfaces in contact. So, when one object moves over the other, these irregularities on the surface get entangled, giving rise to friction.
2. The more the roughness, the more irregularities and more significant will be the friction.
3. Frictional force is a contact force.
4. Frictional force is the force created when two surfaces contact and slide against one another.

Hence, the object will not experience any force of friction because friction requires two surfaces.