401 No friction, no motion

  • Contact force arises when two surfaces come into contact. This contact force is often resolved into two components:
    • The component perpendicular to the surfaces is called the normal contact force N. This force arises because the two surfaces are pressing into each other.
    • The component parallel to the surfaces is called friction f. This force arises when two surfaces are sliding, or are tending to slide, relative to each other.

contact force.gif

  • The direction of friction is always to (try to) prevent the two surfaces to slide relative to each other.
  • Sometimes friction retards motion.

relativeMotion1

  • Sometimes friction produces motion

relativeMotion2

Many people think of friction as a motion-destroying force. That is just so wrong.

Friction does not oppose motion. Friction opposes relative motion. As such, friction is as capable of creating motion as destroying it.  See video below for proof.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s