Final answer:
Over-flat tires are more likely to have a blowout, and under-inflated tires wear the sides of the tire.
Step-by-step explanation:
Tire pressure is an important factor in tire performance.
Over-flat tires are more likely to have a blowout because the lack of air pressure causes the tire to become less rigid and more susceptible to bursting. On the other hand, under-inflated tires wear the sides of the tire because the lack of air pressure causes the tire to flex more, leading to increased friction with the road.
Another example where more friction is desirable is during braking. When you apply the brakes in a car, the brake pads create friction with the brake disc or drum, generating heat and helping to slow down the vehicle.