Mechanical Engineering - Engineering Mechanics - Discussion

Thank you too much for this, really before I did not understand it. Can you please give me explanation for other options?

In nature friction is only three types are available in air we called air resistance in liquids we called -viscosity in Solids we called friction. According to discussion friction basically two types 1st static friction and 2nd dynamic friction according to discussion dynamic means motion (any object which can observed as motion) and friction is surface property which can exert when two or more then bodies are contact and also known motion opposing force.

And dynamic friction is define when body is experienced motion then those force exert on body as a retarding parameter or to reduce the motion of body then body experienced dynamic friction.

If a body is in motion it experience a friction with the surface is called kinetic friction, if dynamic friction=kinetic friction then I agree that is dynamic friction.

When motion of body which restricted by any body who applied restricted force is called friction force, also we say any body restricted apposite direction of motion is called friction force.

When body in motion it is called as dynamic friction.

When a body is in contact with other body and having a movement then the opposing force is called dynamic friction.