Friction helps starting and stopping of moving objects relative to another surface or object.
1. Ice skating
2. Vehicle tyres traveling on road, friction between brakes and wheels. and between tyres and road.
3. people walking on road..
4. Friction allows people to run fast and play games like badminton, cricket.
1. In machines the moving and rotating objects (wheels, shafts) get heated up and get worn out. The life time of the tools is shortened.
2. When people slip or fall on a floor (by self or due to collisions), people get injured and skin gets burnt / damaged. This is due to friction between the floor/road and the body.
3. Bad friction is when a sharp object scratches our skin or sharp objects create scratches on shining tables, shining objects.