Question

a car is driving around a circular bend on a flat road. how does the friction between the tires and the road affect the centripetal force?
a) friction reduces the centripetal force required to maintain the turn
b) friction increases the cars speed while turning
c) friction has no effect on centripetal force
d) friction is responsible for providing the necessary centripetal force

Explanation:

Step1: Analyze centripetal force formula

The centripetal force \(F_c=\frac{mv^{2}}{r}\) (where \(m\) is mass of car, \(v\) is speed, \(r\) is radius of circular path). On a flat road, for a car taking a turn, the frictional force \(f\) provides the centripetal force \(F_c\).

Step2: Evaluate each option

• Option a: The centripetal force required is \(F_c=\frac{mv^{2}}{r}\), friction does not reduce this value.
• Option b: Friction is not responsible for increasing speed while turning. The engine provides power for speed change (if any) and friction here is for circular motion.
• Option c: Friction is the source of centripetal force on a flat road, so it is not correct.
• Option d: Since \(F_c = f\) (frictional force provides centripetal force on a flat road), this option is correct.

Answer:

d) Friction is responsible for providing the necessary centripetal force