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Explore the concept of friction and how it is influenced by surface roughness and material composition. Learn about static, sliding, and rolling friction and how they affect the motion of objects in contact.
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Chapter 3.3 Friction
Question #1 • Friction is resistance force. • Friction is defined as the force that opposes the sliding or rolling motion of two surfaces that are in contact.
Question #2 • The two factors that friction is dependent upon are • the composition of the materials • the roughness of the surfaces of the materials
A CLOSER LOOK: SANDPAPER • Friction is caused by the irregularities in the surfaces of objects that are touching. • Even very smooth surfaces have microscopic irregularities that • obstruct motion. The rougher the surface, the ______________ the friction. greater
Question #3 • Friction increases when the two surfaces pushed together with more force. This increases the strength of the microwelds. • Friction can also increase as the roughness of the surfaces increases.
Question #4 • Static friction (prevents two surfaces in contact from sliding or rolling past each other) • Sliding friction (force acts in the opposite direction to the motion of the object causing it to slow down) • Rolling friction (force resists rolling causing it to slow down--similar to sliding but usually much less than sliding)
HOW DOES THE SURFACE INFLUENCE FRICTION? sliding sliding rolling
WHICH TYPE OF FRICTION? rolling sliding
WHICH TYPE OF FRICTION? sliding rolling
Question #5 • For objects at rest, the applied force must be strong enough to break the microwelds. After the microwelds are broken, the object requires less force to overcome sliding friction. http://www.regentsprep.org/regents/physics/phys01/friction/default.htm