How is friction useful in everyday life?

Answer 1

It helps clean clothes in the washer.

Friction is important in all aspects of life. Friction is a contact force caused by interactions at the molecular level. If friction was not present, any object accelerated on a flat surface would continue to move in that direction infinitely, or until it met an obstruction on that surface.

Similarly, without friction, locomotion (moving) would not be possible because we would have no way of establishing contact with any surface. Our feet (or anything, for that matter) would not "grip" any surface, but rather accelerate across it in the direction of the muscle movement.

Situations like these do not arise because there is no such thing as a completely frictionless surface. Friction, in terms of how it is used on Earth, can be very helpful in preventing motion. For example, it is the force of friction that allows brake pads to squeeze the rotors of a car's wheel, thus converting the kinetic energy of the moving vehicle into thermal energy, slowing it down.