Question

Which of the following is the assumption on the property of the surface on which block is present in case we are dealing with the calculations involving the friction?

(a) Non-rigid

(b) Coloured red

(c) Having density in negative

(d) The motion of that block is always horizontal

The question was asked during an interview.

I would like to ask this question from Problems Involving Dry Friction topic in division Friction of Engineering Mechanics

Answer 1

Right choice is (a) Non-rigid

Easy explanation: The block used to explain the theory of friction is used in a deformable surface. As we know that the theory of friction says that when there is no lubricating fluid present between the surfaces in contact, the dry friction occurs. Thus to show the same experiments are done over a non-rigid/deformable surface.