91Ó°ÊÓ

Whenever a specific surface is referred to as frictionless, it means the surface would not offer any friction force. The relation between the friction force and friction coefficient of the surface material is a direct linear one.

The free-body diagram of block A if the table is frictionless is given below.

Here, ${\mathrm{W}}_{\mathrm{A}}$is the weight of block A, ${\mathrm{N}}_{\mathrm{A}}$is the normal reaction force on block A and ${\mathrm{F}}_{\mathrm{f}}$is the friction force that acts on block A due to the friction between block A and block B.

Since the table is frictionless, the friction force between the table and block A does not exist and results as the value of friction force acts on block A would be equal to the value of pull force.

In the free-body diagram of block A if there is friction between block B and the table and the pull is equal in magnitude to the friction force on block B due to the table is given below.

Here, ${\mathrm{W}}_{\mathrm{A}}$is the weight of the block A and ${\mathrm{N}}_{\mathrm{A}}$is the normal reaction force on block A.

Since the pull is equal in magnitude to the friction force on block B due to the table, block B would be stationary, resulting in block A being also stationary. Therefore, the friction force between block A and block B would not exist.