Friction is a force that resists the movement of two surfaces that are in contact with each other. It is caused by the microscopic irregularities on the surfaces, which create resistance when they come into contact.
Work is done by friction when a force is applied to an object and the object moves against a surface with friction. The work done is equal to the force applied multiplied by the distance the object moves.
Some examples of work done by friction include rubbing your hands together to generate heat, using sandpaper to smooth out wood, and the brakes of a car slowing down the wheels.
The coefficient of friction is a measure of how much friction exists between two surfaces. The higher the coefficient of friction, the more work is done by friction when an object moves against the surface.
Yes, friction can be beneficial in certain situations. For example, it helps us walk without slipping, it allows us to write with a pen or pencil, and it helps vehicles to grip the road. However, too much friction can also be detrimental and cause wear and tear on surfaces.