What is an exapmle of when the friction force is needed???

while driving a vehicle the engine generates force on the driving wheels

Explanation:

k it's not the best but not the worst i wrote this in my test sry if it's wrong

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.

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