Frictional force between solids operates even when they do not move with respect to each other. Do we have viscous force acting between two layers even if there is no relative motion?

Can you think of two particles which do not exert gravitational force on each other?

A block of mass m slips on a rough horizontal table under the action of horiozontal force applied to it. The coefficient of friction between the block and the table is mu . The table does not move on the floor. Find the total frictional force aplied by the floor on the legs of the table. Do you need the friction coefficient between the table and the floor or the mass of the table ?

Can you think of two particles which do not exert gravitational force on each other why? (AS_(2))

Give two points of similarity between viscous force and solid friction?

Two identical solid copper sphere of radius R are placed in contact with each other. The gravitational force between them is proportional to.

Two bodies A and B of masses 5 kg and 10 kg in contact with each other rest on a table against a rigid wall . The coefficient of friction between the bodies and the table is 0.15. A force of 200 N is applied horizontally to A. What are (a) the reaction of the partition (b) the action-reaction forces between A and B ? What happens when the wall is removed? Does the answer to (b) change, when the bodies are in motion? Ignore the difference between mu_s and mu_k

A boy presses a book against the front wall such that the book do not move the force of friction between the wall and the book is

A block is placed on the horizontal surface. There are two forces acting on the block. One, the downward pull of gravity and other a normal force acting on it. Are these forces equal and opposite? Do they form action - reaction pair? Discuss with your friends.

In the section 3.7.3 (Banking of road) we have not included the friction exerted by the road on the car. Suppose the coefficient of static friction between the car tyre and the surface of the road is mu_s , calculate the minimum speed with which the car can take safe turn? When the car takes turn in the banked road, the following three forces act on the car. (1) The gravitational force mg acting downwards (2) The normal force N acting perpendicular to the surface of the road (3) The static frictional force f acting on the car along the surface.