Force of friction

(A) : Force of friction applied by ground on the wheels of a bicycle is always in the direction of motion of the bicycle . (R) : Force of friction always opposes the relative motion between the surfaces in contact .

Statement I: The coefficient of friction can be greater than unity. Statement II: The force of friction is dependent on normal reaction and the ration of force of friction and normal reaction cannot exceed unity.

Assertion : The forces of friction arise due ot gravitational attraction. Reason : The gravitational forces can be attractive and repulsive.

Do the forces of friction and other contact fores aries due to gravitational attraction ? If not, what is the origin of these force?

Define frictional force ( or friction) .

Motion of a spinning ‘top’ is an example of A. Centripetal Force B. Centrifugal Force C. Gravitational Force D. Frictional Force

Pseudo Force|| Friction

Pseudo Force|| Friction

Biological forces, mechanical forces and frictional forces are the examples of: